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Showing new listings for Wednesday, 28 May 2025
- [1] arXiv:2505.20328 [pdf, other]
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Title: A Cosmic Ray Acceleration Mechanism Based on Background Flow Velocity Inhomogeneities Yielding Power-Law SpectraSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
In this article, momentum transport generated by the combined effects of pitch-angle diffusion and Background Flow Velocity Inhomogeneities (BFVIs) is proposed to obtain a cosmic rays acceleration mechanism, starting from the well-known focusing equation describing particle diffusion and acceleration. The inhomogeneities of background flow velocity is ubiquitous in astrophysical environment. The isotropic distribution function equation of charged energetic particles is derived, and its solution is obtained, demonstrating the form of momentum power laws of cosmic rays. In addition, if it is assumed that cosmic rays penetrate compressible plasma waves or turbulence, for quasi-steady states, the spectral index $\delta$ of the momentum power law spectrum of cosmic rays is found to be in the range $[-5, -3]$, which includes the observed power law indices of galactic cosmic rays. The results obtained in this article demonstrate that the mechanism proposed in this article, along with shock acceleration, may also contribute to the acceleration of galactic cosmic rays. Furthermore, when momentum convection effect and higher-order momentum derivative terms are considered, the indices of power laws should be smaller than $-5$. This may explain the power laws of solar energetic particle events.
- [2] arXiv:2505.20363 [pdf, other]
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Title: The Paris Meudon ground based support to the NASA Solar Maximum Mission in the eightiesJean-Marie Malherbe (LIRA, PSL)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
The Solar Maximum Mission of NASA was one of the first satellites with on board digitization of observations. It was launched for the solar maximum of cycle 21 (1980) in order to study the solar activity. It carried many instruments, such as coronagraphs, X and $\gamma$ ray detectors, an Ultra Violet spectrometer and a radiometer. Ground based support was offered by many institutes, such as Paris Meudon observatory under the form of systematic observations or coordinated campaigns with specific instruments. We present here the Meudon Solar Tower (MST) and magnetograph which offered in the eighties a major contribution with observations of velocity and magnetic fields of the photosphere and chromosphere, while SMM was observing the transition region and corona above.
- [3] arXiv:2505.20383 [pdf, html, other]
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Title: Across the Universe: Dark Matter and Galaxy Cross-Correlations with the Cherenkov Telescope Array ObservatoryElena Pinetti, Veronika Vodeb, Aurelio Amerio, Alessandro Cuoco, Stefano Camera, Nicolao Fornengo, Gabrijela ZaharijasComments: 9 pages + Appendix, 28 FiguresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The Cherenkov Telescope Array Observatory (CTAO) will be a ground-based Cherenkov telescope performing wide-sky surveys, ideal for anisotropy studies such as cross-correlations with tracers of the cosmic large-scale structure. Cross-correlations can shed light on high-energy $\gamma$-ray sources and potentially reveal exotic signals from particle dark matter. In this work, we investigate CTAO sensitivity to cross-correlation signals between $\gamma$-ray emission and galaxy distributions. We find that by using dense, low-redshift catalogs like 2MASS, and for integration times around 50 hours, this technique achieves sensitivities to both annihilating and decaying dark matter signals that are competitive with those from dwarf galaxy and cluster analyses.
- [4] arXiv:2505.20391 [pdf, html, other]
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Title: Ambipolar diffusion and the mass-to-flux ratio in a turbulent collapsing cloudComments: 11 pages, 13 figures. Submitted to A&A. Comments are welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA)
The formation of stars is governed by the intricate interplay of nonideal magnetohydrodynamic (MHD) effects, gravity, and turbulence. Computational challenges have hindered a comprehensive 3D exploration of this interplay, posing a longstanding challenge in our understanding of clouds and cores. Our objective was to study the spatial features and time evolution of the neutral-ion drift velocity and the mass-to-flux ratio in a 3D nonideal MHD chemo-dynamical simulation of a supercritical turbulent collapsing molecular cloud. The resistivities of the cloud were computed self-consistently from a vast non-equilibrium chemical network containing 115 species. To compute the resistivities we used different mean collisional rates for each charged species in our network. We additionally developed a new generalized method for measuring the true mass-to-flux ratio in 3D simulations. Despite the cloud's turbulent nature, at early times, the neutral-ion drift velocity follows the expected structure from 2D axisymmetric non-ideal MHD simulations with an hourglass magnetic field. At later times, however, the neutral-ion drift velocity becomes increasingly complex, with many vectors pointing outward from the cloud's center. Specifically, we find that the drift velocity above and below the cloud's ``midplane'' is in ``antiphase''. We explain these features on the basis of magnetic helical loops and the correlation of the drift velocity with the magnetic tension force per unit volume. Despite the complex structure of the neutral-ion drift velocity, we demonstrate that, when averaged over a region, the true mass-to-flux ratio monotonically increases as a function of time and decreases as a function of the radius from the center of the cloud. In contrast, the ``observed'' mass-to-flux ratio shows poor correlation with the true mass-to-flux ratio and the density structure of the cloud.
- [5] arXiv:2505.20392 [pdf, html, other]
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Title: Exploring the interplay of dust and gas phases in DustPedia star-forming galaxiesComments: 12 pages, 7 figures, 1 table, 6 appendices Accepted and in press at A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
Molecular gas is the key ingredient of the star formation cycle, and tracing its dependencies on other galaxy properties is essential for understanding galaxy evolution. In this work, we explore the relation between the different phases of the interstellar medium (ISM), namely molecular gas, atomic gas, and dust, and galaxy properties using a sample of nearby late-type galaxies. To this goal, we collect CO maps for 121 galaxies from the DustPedia project, ensuring an accurate determination of $M_{H2}$, the global molecular gas mass. We investigate which scaling relations provide the best description of $M_{H2}$, based on the strength of the correlation and its intrinsic dispersion. Commonly used correlations between $M_{H2}$ and star formation rate (SFR) and stellar mass ($M_{\star}$) are affected by large scatter, which accounts for galaxies that are experiencing quenching of their star formation activity. This issue can be partially mitigated by considering a "fundamental plane" of star formation, fitting together $M_{H2}$, $M_{\star}$, and SFR. We confirm previous results from the DustPedia collaboration that the total gas mass has the tightest connection with the dust mass and that the molecular component also establishes a good correlation with dust. Although dust grains are necessary for the formation of hydrogen molecules, the strength of gravitational potential driven by the stellar component plays a key role in driving density enhancements and the atomic-to-molecular phase transition. Eventually, we investigated the correlations between ISM components and monochromatic luminosities at different wavelengths: we proposed mid and far-IR luminosities as reliable proxies of $L^{\prime}_{CO}$ for sources lacking dedicated millimeter observations. Luminosities in mid-IR photometric bands collecting PAH emission can be used to trace molecular gas and dust masses.
- [6] arXiv:2505.20393 [pdf, other]
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Title: NEXUS: A Spectroscopic Census of Broad-line AGNs and Little Red Dots at $3\lesssim z\lesssim 6$Ming-Yang Zhuang, Junyao Li, Yue Shen, Xiaojing Lin, Alice E. Shapley, Feige Wang, Qiaoya Wu, Qian YangComments: 26 pages, 17 figures, 4 tables. Submitted to ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a spectroscopic sample of 23 broad-line AGNs (BLAGNs) at $3\lesssim z\lesssim 6$ selected using F322W2+F444W NIRCam/WFSS grism spectroscopy of the central 100 ${\rm arcmin^2}$ area of the NEXUS survey. Among these BLAGNs, 15 are classified as Little Red Dots (LRDs) based on their rest-frame UV-optical spectral slopes and compact morphology. The number density of LRDs is $\sim 10^{-5}\,{\rm cMpc^{-3}}$, with a hint of declining towards the lower end of the probed redshift range. These BLAGNs and LRDs span broad H$\alpha$ luminosities of $\sim 10^{42.2}-10^{43.7}\,{\rm erg\,s^{-1}}$, black hole masses of $\sim 10^{6.3}-10^{8.4}\,M_\odot$, and Eddington ratios of $\sim 0.1-1$ (median value 0.4), though the black hole mass and Eddington ratio estimates carry large systematic uncertainties. Half of the LRDs show strong Balmer absorption, suggesting high-density gas surrounding the line-emitting region. We detect extended (hundreds of parsec) rest-frame UV-optical emission from the host galaxy in the majority of these LRDs, which contributes significantly or even dominantly to their total UV emission. This host emission largely accounts for the peculiar UV upturn of the LRD spectral energy distribution. We also measure the small-scale ($\lesssim 1\,{\rm cMpc}$) clustering of these BLAGNs and LRDs by cross-correlating with a photometric galaxy sample. Extrapolating the power-law two-point correlation function model to large linear scales, we infer a linear bias of $3.30_{-2.04}^{+2.88}$ and typical halo masses of a few $\times 10^{11}\,h^{-1}M_\odot$ for BLAGNs at the sample median redshift of $z\sim 4.5$. However, the inferred linear bias and halo masses of LRDs, while formally consistent with those for BLAGNs at $\sim 1.5\sigma$, appear too large to be compatible with their space density, suggesting LRDs may have strong excess clustering on small scales.
- [7] arXiv:2505.20394 [pdf, html, other]
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Title: gallifrey: JAX-based Gaussian process structure learning for astronomical time seriesComments: 16 pages, 10 figures, 3 tables, accepted in A&A, code available at this https URL, documentation available at this https URLSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
Gaussian processes (GPs) have become a common tool in astronomy for analysing time series data, particularly in exoplanet science and stellar astrophysics. However, choosing the appropriate covariance structure for a GP model remains a challenge in many situations, limiting model flexibility and performance. This work provides an introduction to recent advances in GP structure learning methods, which enable the automated discovery of optimal GP kernels directly from the data, with the aim of making these methods more accessible to the astronomical community. We present gallifrey, a JAX-based Python package that implements a sequential Monte Carlo algorithm for Bayesian kernel structure learning. This approach defines a prior distribution over kernel structures and hyperparameters, and efficiently samples the GP posterior distribution using a novel involutive Markov chain Monte Carlo procedure. We applied gallifrey to common astronomical time series tasks, including stellar variability modelling, exoplanet transit modelling, and transmission spectroscopy. We show that this methodology can accurately interpolate and extrapolate stellar variability, recover transit parameters with robust uncertainties, and derive transmission spectra by effectively separating the background from the transit signal. When compared with traditional fixed-kernel approaches, we show that structure learning has advantages in terms of accuracy and uncertainty estimation. Structure learning can enhance the performance of GP regression for astronomical time series modelling. We discuss a road map for algorithmic improvements in terms of scalability to larger datasets, so that the methods presented here can be applied to future stellar and exoplanet missions such as PLATO.
- [8] arXiv:2505.20396 [pdf, html, other]
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Title: Cosmological impact of $ν$DM interactions enhanced in narrow redshift rangesComments: 10 pages, 4 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The impact of dark matter-neutrino ($\nu$DM) interactions on cosmological perturbations has regained attention, spurred by indications of non-zero couplings from high-multipole cosmic microwave background data, weak lensing, and Lyman-$\alpha$ observations. We demonstrate that a similar observational preference is obtained if $\nu$DM interactions are primarily enhanced during a specific epoch, $z\sim (10^4-10^5)$, leading to $>3\sigma$ preference for a non-zero interaction in the combined Atacama Cosmology Telescope and cosmic shear data. This redshift-limited enhancement circumvents other cosmological and astrophysical bounds and can be achieved within a neutrino portal dark matter framework incorporating resonantly enhanced scattering rates.
- [9] arXiv:2505.20399 [pdf, html, other]
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Title: ULULA: An ultra-lightweight 2D hydrodynamics code for teaching and experimentationComments: 11 pages, 8 figures. Comments welcome. Documentation at this https URLSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Hydrodynamics is a difficult subject to teach in the classroom because most relevant problems must be solved numerically rather than analytically. While there are numerous public hydrodynamics codes, the complexity of production-level software obscures the underlying physics and can be overwhelming to first-time users. Here we present ULULA, an ultra-lightweight python code to solve hydrodynamics and gravity in 2D. The main goal is for the code to be easy to understand, extend, and experiment with. The simulation framework consists of fewer than 800 active lines of pure python code, but it includes a robust MUSCL-Hancock scheme with exchangeable components such as Riemann solvers, reconstruction schemes, boundary conditions, and equations of state. Numerous well-known hydrodynamics problems are provided and can be run in a few minutes on a laptop. The code is open-source, generously commented, and extensively documented.
- [10] arXiv:2505.20407 [pdf, html, other]
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Title: Neutral gas phase distribution from HI morphology: phase separation with scattering spectra and variational autoencodersSubjects: Astrophysics of Galaxies (astro-ph.GA)
Unraveling the multi-phase structure of the diffuse interstellar medium (ISM) as traced by neutral hydrogen (HI) is essential to understanding the lifecycle of the Milky Way. However, HI phase separation is a challenging and under-constrained problem. The neutral gas phase distribution is often inferred from the spectral line structure of HI emission. In this work, we develop a data-driven phase separation method that extracts HI phase structure solely from the spatial morphology of HI emission intensity structures. We combine scattering spectra (SS) statistics with a Gaussian-mixture variational autoencoder (VAE) model to: 1. derive an interpretable statistical model of different HI phases from their multi-scale morphological structures; 2. use this model to decompose the 2D channel maps of GALFA-HI emission in diffuse high latitude ($|b|>30$\degree) regions over narrow velocity channels ($\Delta v=3$ km/s) into cold neutral medium (CNM), warm neutral medium (WNM), and noise components. We integrate our CNM map over velocity channels to compare it to an existing map produced by a spectrum-based method, and find that the two maps are highly correlated, while ours recovers more spatially coherent structures at small scales. Our work illustrates and quantifies a clear physical connection between the HI morphology and HI phase structure, and unlocks a new avenue for improving future phase separation techniques by making use of both HI spectral and spatial information to decompose HI in 3D position-position-velocity (PPV) space. These results are consistent with a physical picture where processes that drive HI phase transitions also shape the morphology of HI gas, imprinting a sparse, filamentary CNM that forms out of a diffuse, extended WNM.
- [11] arXiv:2505.20413 [pdf, html, other]
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Title: Disentangling the Halo: Joint Model for Measurements of the Kinetic Sunyaev-Zeldovich Effect and Galaxy-Galaxy LensingJames Sunseri, Alexandra Amon, Jo Dunkley, Nicholas Battaglia, Simone Ferraro, Boryana Hadzhiyska, Bernadita Ried Guachalla, Emmanuel SchaanComments: 14 pages, 6 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
We present the first joint analysis of the kinetic Sunyaev-Zeldovich (kSZ) effect with galaxy-galaxy lensing (GGL) for CMASS galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS). We show these complementary probes can disentangle baryons from dark matter in the outskirts of galactic halos by alleviating model degeneracies that are present when fitting to kSZ or GGL measurements alone. In our joint kSZ+GGL analysis we show that the baryon density profile is well constrained on scales from 0.3 to 50 Mpc/$h$. With our well constrained profile of the baryon density, we provide direct comparisons to simulations. For our model we find an outer slope of the baryon distribution that is shallower than predicted by some hydrodynamical simulations, consistent with enhanced baryonic feedback. We also show that not including baryons in a model for GGL can bias halo mass estimates low by $\sim 20\%$ compared to a model that includes baryons and is jointly fit to kSZ+GGL measurements. Our modelling code galaxy-galaxy lensing and kSZ (\texttt{glasz}) is publicly available at this https URL.
- [12] arXiv:2505.20427 [pdf, html, other]
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Title: Burned to ashes: How the thermal decomposition of refractory organics in the inner protoplanetary disc impacts the gas-phase C/O ratioAdrien Houge, Anders Johansen, Edwin Bergin, Fred J. Ciesla, Bertram Bitsch, Michiel Lambrechts, Thomas Henning, Giulia PerottiComments: Accepted for publication in A&A. 18 pages, 14 figures, 1 tableSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The largest reservoir of carbon in protoplanetary discs is stored in refractory organics, which thermally decompose into the gas-phase at the organics line, well interior to the water iceline. Because this region is so close to the host star, it is often assumed that the released gaseous material is rapidly accreted and plays little role in the evolution of the disc composition. However, laboratory experiments show that the thermal decomposition process is irreversible, breaking macromolecular refractory organics into simpler, volatile carbon-bearing compounds. As a result, unlike the iceline of other volatiles, which traps vapor inwards due to recondensation, the organics line remains permeable, allowing gaseous carbon to diffuse outward without returning to the solid phase. In this paper, we investigate how this process affects the disc composition, particularly the gas-phase C/H and C/O ratios, by incorporating it into a 1D evolution model for gas and solids, and assuming refractory organics dominantly decompose into C$_2$H$_2$. Our results show that this process allows this carbon-rich gas to survive well beyond the organics line (out to $7 \mathrm{~au}$ around a solar-mass star) and for much longer timescales, such that its abundance is increased by an order of magnitude. This has several implications in planet formation, notably by altering how the composition of solids and gas relate, and the fraction of heavy elements available to giant planets. In the framework of our model, refractory organics significantly influence the evolution of the gas-phase C/O ratio, which may help interpreting measurements made with Spitzer and JWST.
- [13] arXiv:2505.20430 [pdf, html, other]
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Title: DESI Emission Line Galaxies: Clustering Dependence one Stellar Mass and [OII] LuminosityT. Hagen, K. S. Dawson, Z. Zheng, J. Aguilar, S. Ahlen, S. BenZvi, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, A. de la Macorra, P. Doel, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztanaga, S. Gontcho A Gontcho, V. Gonzalez-Perez, G. Gutierrez, C. Hahn, K. Honscheid, M. Ishak, S. Juneau, R. Kehoe, T. Kisner, A. Kremin, C. Lamman, M. Landriau, L. Le Guillou, A. Leauthaud, M. E. Levi, M. Manera, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, N. Palanque-Delabrouille, F. Prada, I. Perez-Rafols, A. J. Ross, G. Rossi, S. Saito, E. Sanchez, D. Schlegel, M. Schubnell, J. Silber, D. Sprayberry, G. Tarle, B. A. Weaver, R. Zhou, H. ZouSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We measure the projected two-point correlation functions of emission line galaxies (ELGs) from the Dark Energy Spectroscopic Instrument (DESI) One-Percent Survey and model their dependence on stellar mass and [OII] luminosity. We select $\sim$180,000 ELGs with redshifts of $0.8 < z < 1.6$ and define 27 samples according to cuts in redshift and both galaxy properties. Following a framework that describes the conditional [OII] luminosity-stellar mass distribution as a function of halo mass, we simultaneously model the clustering measurements of all samples at fixed redshift. Based on the modeling result, most ELGs in our samples are classified as central galaxies, residing in halos of a narrow mass range with a typical median of $\sim$10$^{12.2-12.4}$ $h^{-1} M_\odot$. We observe a weak dependence of clustering amplitude on stellar mass, which is reflected in the model constraints and is likely a consequence of the 0.5-dex measurement uncertainty in the stellar mass estimates. The model shows a trend between galaxy bias and [OII] luminosity at high redshift ($1.2 < z < 1.6$) that is otherwise absent at lower redshifts.
- [14] arXiv:2505.20432 [pdf, html, other]
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Title: Evolution of star clusters with initial bulk rotation via N-body simulationsAbylay Bissekenov, Xiaoying Pang, Albrecht Kamlah, M.B.N. Kouwenhoven, Rainer Spurzem, Bekdaulet Shukirgaliyev, Mirek Giersz, Abbas Askar, Peter BerczikSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Young star clusters can inherit bulk rotation from the molecular clouds from which they have formed. This rotation can affect the long-term evolution of a star cluster and its constituent stellar populations. In this study, we aim to characterize the effects of different degrees of initial rotation on star clusters with primordial binaries. The simulations are performed using NBODY6++GPU. We find that initial rotation strongly affects the early evolution of star clusters. Rapidly rotating clusters show angular momentum transport from the inner parts to the outskirts, resulting in a core collapse. Angular momentum transport is accompanied by a highly elongated bar-like structure morphology. The effects of bulk rotation are reduced on the timescale of two-body relaxation. Rotating and non-rotating clusters experience changes in the direction of angular momentum near the dissolution and early evolution due to the tidal field, respectively. We present synthetic observations of simulated clusters for comparison with future observations in filters of Gaia, CSST, and HST. This work shows the effects of bulk rotation on systems with primordial binaries and could be used for the identification of rotation signatures in observed open clusters.
- [15] arXiv:2505.20439 [pdf, html, other]
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Title: The Properties of Little Red Dot Galaxies in the ASTRID SimulationPatrick LaChance, Rupert A.C. Croft, Tiziana Di Matteo, Yihao Zhou, Fabio Pacucci, Yueying Ni, Nianyi Chen, Simeon BirdComments: 15 pages, 12 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
We present simulated counterparts of the ``Little Red Dot'' (LRD) galaxies observed with JWST, using the large cosmological hydrodynamic simulation, ASTRID. We create mock observations of the galaxies ($5 \leq z \leq 8$) in ASTRID, and find seventeen which fit the color and size criteria of LRDs. These LRDs are galaxies with high stellar masses ($\rm log(M_*/M_{\odot}) \geq 9.7$), and massive black holes ($\rm log(M_{BH}/M_{\odot}) \geq 6.8$). The host galaxies are dense, with stellar half mass radii ($\rm 325\,pc \leq r_{{\rm half},*} \leq 620\,pc$), and dust attenuation in the F444W band above 1.25. Their star formation has been recently quenched. They host relatively bright AGN that are dust-obscured and contribute significantly to the rest-frame optical red slope and have relatively low luminosity in the rest-frame ultraviolet, where the host galaxy's stars are more dominant. These LRDs are in an evolutionary phase of miniquenching that is the result of AGN feedback from their massive black holes. The LRDs in ASTRID are bright with F444W magnitudes of $23.5-25.5$. The less massive and fainter galaxies in ASTRID lack the dust concentration necessary to produce the red slope of an LRD, though this could be an effect of limited resolution. Most of the highest Eddington black holes are not LRDs due to their host galaxies having typical dust levels and relatively high star formation rates accompanying their highly accreting black holes, resulting in their spectra being too flat.
- [16] arXiv:2505.20453 [pdf, html, other]
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Title: NuSTAR Observations of the Galaxy Cluster Abell 3667Comments: 8 pages, 3 figures, 1 table. Accepted for publication in PASASubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present an analysis of the hard X-ray emission from the central region of Abell 3667 using deep NuSTAR observations. While previous studies on the nature of the hard X-ray excess have been controversial, our analysis of the central region suggests that the excess is primarily thermal, best described by a two-temperature (2T) model, with the high-temperature component likely arising from merger-induced heating. This interpretation contrasts with some earlier suggestions of non-thermal emission due to inverse Compton scattering of relativistic electrons. Additionally, we set a lower limit on the magnetic field strength of $\sim 0.2 \, \mu$G in the central region, consistent with values found in other dynamically active clusters and compatible with those inferred from equipartition and Faraday rotation measurements. Since our study is focused on the central region of the cluster, further high-resolution observations of the outer regions will be critical to fully disentangle the thermal and non-thermal contributions to the X-ray.
- [17] arXiv:2505.20461 [pdf, html, other]
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Title: Jupiter's UV auroral response to a magnetospheric compression eventR. S. Giles, T. K. Greathouse, R. W. Ebert, W. S. Kurth, C. K. Louis, M. F. Vogt, B. Bonfond, D. Grodent, J.-C. Gérard, G. R. Gladstone, J. A. Kammer, V. Hue, R. J. Wilson, S. J. Bolton, J. E. P. ConnerneyComments: Accepted in JGR: PlanetsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The highly elliptical polar orbit of the Juno mission provides a unique opportunity to simultaneously measure the compression state of Jupiter's magnetosphere and the total power emitted by the planet's ultraviolet aurora, using a single spacecraft. This allows us to study how Jupiter's aurora respond to a compression event. In this paper, we present a case study of an extreme compression event that occurred on December 6-7 2022 when Juno was a distance of 70 R$_{J}$ from Jupiter. This extreme compression was accompanied by a very large increase in the ultraviolet auroral emissions to 12 TW, a factor of six higher than the baseline level. This event coincided with the predicted arrival of a powerful interplanetary shock, which was expected to cause the largest increase in the solar wind dynamic pressure seen thus far during the Juno mission. The simultaneous occurrence of the interplanetary shock, the extreme compression and the bright ultraviolet aurora suggests that in this case, the auroral brightening was caused by the solar wind shock compressing the magnetosphere.
- [18] arXiv:2505.20470 [pdf, html, other]
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Title: Gaseous Dynamical Friction on Hyperbolic ScatteringsComments: Submitted to ApJ. Comments are welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
We present a study of equal-mass hyperbolic encounters, embedded in a uniform gaseous medium. Using linear perturbation theory, we calculate the density wakes excited by these perturbers and compute the resulting forces exerted on them by the gas. We compute the changes to orbital energy, orbital angular momentum and apsidal precession across a wide range of eccentrities and pericenter Mach numbers. We identify six distinct classes of hyperbolic orbits, differing through their wake structure and subsequent orbital evolution. We find the gas to always dissipate orbital energy, leading to smaller semi-major axes and higher pericenter Mach numbers. The orbital angular momentum can either increase or decrease, whereas we typically find the orbital eccentricity to be damped, promoting supersonic gas-captures. Additionally, we find that the force exerted by the gas is not strictly frictional -- particularly for asymptotically subsonic trajectories. Therefore, despite the orbit-integrated changes to orbital parameters being similar to those predicted by the \cite{O99} prescription, the time evolution of the density wakes and the instantaneous forces exerted on the perturbers are significantly different.
- [19] arXiv:2505.20516 [pdf, html, other]
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Title: Ten Aligned Orbits: Planet Migration in the Era of JWST and ArielComments: Accepted to AJ. arXiv admin note: text overlap with arXiv:2501.05615Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Understanding the diverse formation and migration pathways that shape exoplanetary systems requires characterizing both their atmospheric properties and their orbital dynamics. A key dynamical diagnostic is the projected spin-orbit angle - the alignment between the stellar spin and the planetary orbit-which provides crucial tests for theoretical models. This angle can be determined using the Rossiter-McLaughlin effect. Although measurements exist for over 200 planets, the overall distribution of these angles is not fully understood, motivating further observations across the full parameter space. We analyze archival HARPS and HARPS-N spectroscopic transit time series of nine gas giant exoplanets on short orbits and one brown dwarf. We derive their projected spin-orbit angle $\lambda$. We find aligned projected orbits for all nine gas giants as well as the brown dwarf. Furthermore, we are able to derive the true spin-orbit angle for the brown dwarf EPIC 219388192b, $\psi = $25$^{+11}_{-14}$ deg. These projected prograde orbits are consistent with quiet disc migration disfavoring violent events exciting the orbits in the history of these systems. Finally, we investigate the current overlap between spin-orbit angle measurements and atmospheric characterization targets. While we find no strong observational biases due to the spin-orbit angle, we note that the majority of planets with atmospheric data still lack spin-orbit measurements. This incompleteness of the dynamical information may limit the interpretation of upcoming atmospheric surveys.
- [20] arXiv:2505.20520 [pdf, html, other]
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Title: Highlights from Exoplanet Observations by the James Webb Space TelescopeComments: Comments from the community are very welcome. To be published in: Handbook of Exoplanets, 2nd Edition, Hans Deeg and Juan Antonio Belmonte (Eds. in Chief), Springer International Publishing AG, part of Springer NatureSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The James Webb Space Telescope (JWST) has started a revolution in exoplanetary science. From studying in exquisite detail the chemical inventories and physical processes in gas giant exoplanets, the structure and chemical diversity of the enigmatic sub-Neptune population to even providing constraints on the atmospheric make-up of rocky exoplanets, the observatory is enabling cutting-edge science that is touching virtually every sub-area in the field. In this review Chapter, we showcase key highlights from exoplanet science being conducted with this state-of-the-art space observatory, which we believe is representative of the transformational science it is producing. One of the key takeaways from these pioneering JWST observations is how they are starting to reshape not only how we think, study and interpret exoplanet observations -- but how they are also reshaping our intuition about our very own Solar System planets.
- [21] arXiv:2505.20542 [pdf, html, other]
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Title: Asteroseismic mass and radius of the naked-eye red giant HD145250Comments: Submitted to AAS JournalsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present the first asteroseismic analysis of the bright, nearby red giant star, HD145250. We calculate the global seismic quantities of the star from single-sector, 2-minute TESS photometry, and determine its mass and radius to be ~1.4 M$_\odot$ and ~16 R$_\odot$ using asteroseismic scaling relations. Our values agree with published non-seismic mass and radius estimates based on comparisons with stellar evolutionary models.
- [22] arXiv:2505.20548 [pdf, html, other]
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Title: Semi-analytical model for the dynamical evolution of planetary systems via giant impactsComments: 16 pages, 9 figures, 1 table, accepted for publication in ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
In the standard model of terrestrial planet formation, planets are formed through giant impacts of planetary embryos after the dispersal of the protoplanetary gas disc. Traditionally, $N$-body simulations have been used to investigate this process. However, they are computationally too expensive to generate sufficient planetary populations for statistical comparisons with observational data. A previous study introduced a semi-analytical model that incorporates the orbital and accretionary evolution of planets due to giant impacts and gravitational scattering. This model succeeded in reproducing the statistical features of planets in $N$-body simulations near 1 au around solar-mass stars. However, this model is not applicable to close-in regions (around 0.1 au) or low-mass stars because the dynamical evolution of planetary systems depends on the orbital radius and stellar mass. This study presents a new semi-analytical model applicable to close-in orbits around stars of various masses, validated through comparison with $N$-body simulations. The model accurately predicts the final distributions of planetary mass, semi-major axis, and eccentricity for the wide ranges of orbital radius, initial planetary mass, and stellar mass, with significantly reduced computation time compared to $N$-body simulations. By integrating this model with other planet-forming processes, a computationally low-cost planetary population synthesis model can be developed.
- [23] arXiv:2505.20557 [pdf, html, other]
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Title: Multiverse Predictions for Habitability: The Habitability of Exotic EnvironmentsComments: 21 pages + referencesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
The relative abundances of exotic environments provides us with (uninformed) bounds on the habitability of those environments relative to our own, on the basis that our presence here is not too atypical. For instance, since red stars outnumber yellow stars 7 to 3, we can infer that red stars must be less than 8.1 times as habitable as yellow, as otherwise our presence around a yellow star would be a statistical outlier at the level of $5\%$. In the multiverse context, the relative abundances of exotic environments can be drastically different from those in our universe, which sometimes allows us to place much stronger bounds on their relative habitability than we would get by restricting our attention to our universe. We apply this reasoning to a variety of different exotic environments: tidally locked planets, binary star systems, icy moons, rogue planets, liquids with properties different from water, and waterworlds. We find that the bounds on the relative habitability of rogue planets and waterworlds are at least an order of magnitude stronger in a multiverse context than from our universe alone. Additionally, the belief that some of water's special properties are essential for life, such as the fact that ice floats and, with some caveats, that it acts as a universal solvent, are incompatible with the multiverse hypothesis. If any of these bounds are found to be violated in the future, the multiverse hypothesis can be falsified to a high degree of confidence.
- [24] arXiv:2505.20558 [pdf, html, other]
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Title: Continuous Habitable Zone Metric for Prioritizing Habitable Worlds Observatory TargetsComments: 22 pages, 7 figures, 4 tables, accepted to ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Future direct imaging space telescopes, such as NASA's Habitable Worlds Observatory (HWO), will be the first capable of both detecting and characterizing terrestrial exoplanets in the habitable zones (HZ) of nearby Sun-like stars. Since this will require a significant amount of time and resources for even a single system or exoplanet, the likelihood that a system will host detectable life should be considered when prioritizing observations. One method of prioritization is to estimate the likelihood that an exoplanet has remained continuously within the HZ long enough for life to emerge and make a detectable impact on the atmosphere. We utilize a Bayesian method to calculate the likelihood that a given orbital radius around a star is currently in the 2 Gyr continuous habitable zone (CHZ$_2$), the approximate time it took life on Earth to significantly oxygenate the atmosphere. We apply this method to the 164 stars in the NASA Exoplanet Exploration Program Mission Star List (EMSL) for HWO, representing a preliminary sample of Sun-like stars with HZs most accessible to a future direct imaging mission. By considering the CHZ$_2$ likelihood at all orbital radii outside a hypothetical inner working angle for HWO, we define a metric for prioritizing targets according to the accessibility and total extent of the CHZ$_2$. We find that the CHZ$_2$ metric peaks between $3-4$ Gyr for late-F and early-G dwarfs, but tentatively determine that stars earlier than $\sim {F3}$ or hotter than $\sim 6600$ K are unlikely to have a CHZ$_2$ at the time of observation.
- [25] arXiv:2505.20588 [pdf, html, other]
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Title: Continuous helium absorption from the leading and trailing tails of WASP-107bVigneshwaran Krishnamurthy, Yann Carteret, Caroline Piaulet-Ghorayeb, Jared Splinter, Dhvani Doshi, Michael Radica, Louis-Philippe Coulombe, Romain Allart, Vincent Bourrier, Nicolas B. Cowan, David Lafrenière, Loïc Albert, Lisa Dang, Ray Jayawardhana, Doug Johnstone, Lisa Kaltenegger, Adam B. Langeveld, Stefan Pelletier, Jason F. Rowe, Pierre-Alexis Roy, Jake Taylor, Jake D. TurnerComments: Under review in Nature Astronomy (9 Figures)Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
The detection of helium escaping the atmosphere of exoplanets has revolutionized our understanding of atmospheric escape and exoplanetary evolution. Using high-precision spectroscopic observations from the James Webb Space Telescope (JWST) NIRISS-SOSS mode, we report the detection of significant helium absorption during the pre-transit phase of WASP-107b (17$\sigma$), as well as in the transit and post-transit phases. This unique continuous helium absorption begins approximately 1.5 hours before the planet's ingress and reveals the presence of an extended thermosphere. The observations show a maximum transit depth of 2.395$\% \pm$ 0.01$\%$ near the helium triplet (36$\sigma$; at NIRISS-SOSS resolution $\sim$ 700). Our ellipsoidal model of the planetary thermosphere matches well the measured light curve suggesting an outflow extending to tens of planetary radii. Furthermore, we confidently detect water absorption (log10 H2O=-2.5 $\pm$ 0.6), superimposed with a short-wavelength slope which we attribute to a prominent signature from unocculted stellar spots (5.2$\sigma$), rather than a small-particle haze slope. We place an upper limit on the abundance of K (log10 K$<$-4.86, or K/H$<$ 75$\times$ stellar) at 2$\sigma$, which is consistent with the O/H super-solar metallicity estimate. This study underscores the transformative potential of JWST for tracing atmospheric and mass-loss processes, while offering a benchmark for future studies targeting helium escape and its implications for planetary evolution.
- [26] arXiv:2505.20592 [pdf, html, other]
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Title: Photometric and Spectroscopic Studies of Two Early-Type Eclipsing BinariesComments: 12 pages, 4 figures, 6 tables, accepted by ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Using high-precision photometric data from TESS, medium resolution spectroscopic data from LAMOST, and long-term eclipse timings, we provide orbital parameters for two early-type detached eclipsing binary systems: TYC 3740-2072-1 and TYC 2888-780-1, and analyze the orbital period variations and evolutionary status of these two targets. TYC 3740-2072-1, with a spectral type of B1V, consists of a $6.914 M_\odot$ subgiant and a $6.233 M_\odot$ main-sequence component. It is expected to evolve into a semi-detached binary, potentially serving as a progenitor of a Type Ia supernova. TYC 2888-780-1 has a spectral type of A3 and consists of two main-sequence components with masses of $1.682 M_\odot$ and $1.673 M_\odot$, respectively. It is undergoing stable evolution. Through eclipse timing analysis, we find that both targets exhibit apsidal motion effects, with observed AM rates of $\dot{\omega}_{obs} = 0.0412~\text{deg}~\text{cycle}^{-1}$ and $\dot{\omega}_{obs} = 0.0205~\text{deg}~\text{cycle}^{-1}$, respectively. Additionally, TYC 2888-780-1 exhibits orbital period variations, which we attribute to the light travel time effect caused by a third body, the minimum mass of this third body is estimated to be $0.598 M_\odot$.
- [27] arXiv:2505.20656 [pdf, html, other]
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Title: A joint analysis of 3D clustering and galaxy \times CMB-lensing cross-correlations with DESI DR1 galaxiesM. Maus, M. White, N. Sailer, A. Baleato Lizancos, S. Ferraro, S. Chen, J. DeRose, J. Aguilar, S. Ahlen, S. BenZvi, D. Bianchi, D. Brooks, E. Burtin, F. J. Castander, E. Chaussidon, T. Claybaugh, A. Cuceu, A. de la Macorra, A. de Mattia, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, J. Guy, K. Honscheid, C. Howlett, M. Ishak, R. Kehoe, D. Kirkby, T. Kisner, A. Kremin, O. Lahav, C. Lamman, M. Landriau, L. Le Guillou, M. E. Levi, M. Manera, A. Meisner, R. Miquel, S. Nadathur, J. A. Newman, N. Palanque-Delabrouille, W. J. Percival, F. Prada, I. Pérez-Rà fols, A. J. Ross, G. Rossi, L. Samushia, E. Sanchez, D. Schlegel, M. Schubnell, H. Seo, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, P. Zarrouk, R. Zhou, H. ZouComments: 43 pages, 14 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The spectroscopic data from DESI Data Release 1 (DR1) galaxies enables the analysis of 3D clustering by fitting galaxy power spectra and reconstructed correlation functions in redshift space. Given low measurements of the amplitude of structure from cosmic shear at $z\sim1$, redshift space distortions (RSD) + Baryon Acoustic Oscillation (BAO) signals from DESI galaxies combined with weak lensing can break degeneracies and provide a tight alternative constraint on the $z\sim1$ amplitude of structure. In this paper we perform joint analyses that combine full-shape + post-reconstruction information from the DESI DR1 BGS and LRG samples along with angular cross-correlations with Planck PR4 and ACT DR6 CMB lensing maps. We show that adding galaxy-lensing cross-correlations tightens clustering amplitude constraints, improving $\sigma_8$ uncertainties by $\sim 40\%$ over RSD+BAO alone. We also include angular galaxy-galaxy and galaxy-lensing spectra using photometric samples from the DESI Legacy Survey to further improve constraints. Our headline results are $\sigma_8 = 0.803\pm 0.017$, $\Omega_{\rm m} = 0.3037\pm 0.0069$, and $S_8 = 0.808\pm 0.017$. Given DESI's preference for higher $\sigma_8$ compared to lower values from BOSS, we perform a catalog-level comparison of LRG samples from both surveys. We test sensitivity to dark energy assumptions by relaxing our $\Lambda$CDM prior and allowing for evolving dark energy via the $w_0-w_a$ parameterization. We find our $S_8$ constraints to be relatively unchanged despite a $~3.5\sigma$ tension with the cosmological constant model when combining with the Union3 supernova likelihood. Finally we test general relativity (GR) by allowing the gravitational slip parameter ($\gamma$) to vary, and find $\gamma = 1.17\pm0.11$ in mild ($\sim1.5\sigma$) tension with the GR value of $1.0$.
- [28] arXiv:2505.20669 [pdf, html, other]
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Title: Mapping the Star Formation and HI Gas Properties of Galaxies Along Large-scale Structures Around the Virgo ClusterComments: 24 pages, 14 figures, 4 tables, accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We investigate the star formation and neutral atomic hydrogen (HI) gas properties of galaxies along three large-scale filaments and two galaxy groups in the wide field around the Virgo cluster. Our goal is to understand how galaxies are processed in low-density environments before falling into high-density regions. Combining the spatial distribution of galaxies with multiwavelength colors such as W3-W1, NUV-r, and g-r, we find a predominance of blue galaxies across the structures, indicating normal-to-enhanced star formation, similar to that of isolated galaxies. However, one filament and one group show a significant number of red galaxies (32% and 20%, respectively), suggesting that star formation has been suppressed in low-density environments before reaching high-density regions. Intriguingly, these red galaxies span a wide range of stellar masses, and the presence of red dwarfs support that not only mass but also environment plays an important role in the quenching of star formation in cluster outskirts. One particular filament, potentially connected to Virgo, already has a group of red populations outside Virgo's R_200, making these galaxies good candidates for being "preprocessed" before entering the Virgo cluster. In addition, several galaxies in the filaments and groups possess relatively low HI gas contents, similar to cluster galaxies. However, the overall fraction of HI-deficient galaxies is not as significantly high as the fraction of red galaxies in these structures. This suggests that HI gas properties are less influenced by the environment than star formation properties in low-density regions, possibly due to gas replenishment through accretion.
- [29] arXiv:2505.20706 [pdf, html, other]
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Title: The Quasar-associated 2175 Ã… Dust Absorbers in the SDSS DR16 Quasar CatalogComments: 15 pages, 6 figures, 1 table, submited to ApJSSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present, for the first time, a systematic study of quasar-associated 2175 Ã… dust absorbers using spectroscopic data from the Sloan Digital Sky Survey (SDSS) Data Release 16 (DR16). By analyzing the optical spectra and multi-band magnitudes of 557,674 quasars in the redshift range of $0.7 \le z \le 2.4$, we identify 843 absorbers that share the same redshifts as quasars and are believed to originate from dust in the quasar nuclei, the host galaxies, or their surrounding environments. These absorbers exhibit weak bump strengths ($A\rm_{bump}=0.49\pm0.15~\mu m^{-1}$) and narrow widths ($\gamma\rm=0.81\pm0.14~\mu m^{-1}$), while their peak positions span a broad range from $x_0 = 4.2$ to $4.84~ \mu m^{-1}$. Their average extinction curves resemble those of the Large Magellanic Cloud (LMC) but exhibit a shallower slope. In broad absorption line (BAL) quasars, the absorption bumps show systematic shifts in peak positions. Although further confirmation is needed, this may suggest environmental differences in dust grain properties. We find a statistically significant negative correlation between bump strength and redshift, suggesting possible evolution in dust properties. These findings highlight the changing composition and physical conditions of dust in quasar environments, likely influenced by factors such as metallicity, radiation fields, and dust processing mechanisms. Future studies incorporating ultraviolet and infrared data will be essential for refining the dust evolution models. Machine learning techniques and high-resolution spectroscopic follow-ups could enhance sample completeness and provide deeper insights into the chemical properties of the dust absorbers.
- [30] arXiv:2505.20722 [pdf, html, other]
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Title: Magnetically arrested transmutation of a compact starH. A. Adarsha (MCNS, India), Chandrachur Chakraborty (MCNS, India), Sudip Bhattacharyya (TIFR, India)Comments: 12 pages, 3 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
We introduce a novel mechanism -- Magnetically Arrested Transmutation (MAT) -- to account for the observed absence of ordinary pulsars near the Galactic centre, a longstanding puzzle known as the missing pulsar problem and the over-representation of magnetic white dwarfs in the same region. In this scenario, compact stars capture and accumulate dark matter, eventually forming an endoparasitic black hole (EBH) of initial mass $M_0$ at their core. Although such EBHs generally grow by accreting host matter, we show that sufficiently strong core magnetic fields can establish pressure equilibrium, thereby stalling further accretion and halting the star's transmutation into a black hole. We derive the conditions for MAT to occur, identifying a critical parameter $\beta$, which encapsulates the interplay between the magnetic field strength, host matter density, and EBH mass. For $0 < \beta \leq 4/27$, the growth of the EBH is arrested, limiting its final mass ($M_{\rm f}$) to $M_0 < M_{\rm f} \leq 3/2 M_0$, whereas for $\beta > 4/27$, full transmutation may ensue. This framework offers a plausible unified explanation for the absence of ordinary pulsars and the survival of the magnetar PSR J1745-2900, and the elevated population of magnetic white dwarfs, in the Galactic centre, and hence could be tested and should have implications for understanding dark matter and compact objects.
- [31] arXiv:2505.20762 [pdf, html, other]
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Title: The Extreme Universe Observatory on a Super-Pressure Balloon II: Mission, Payload, and FlightJames.H. Adams Jr., Denis Allard, Phillip Alldredge, Luis Anchordoqui, Anna Anzalone, Mahdi Bagheri, Matteo Battisti, Roberto Bellotti, Alexander Belov, Mario Bertaina, Peter Bertone, Sylvie Blin-Bondil, Jordan Bogdan, Julia Burton Heigbes, Francis Cafagna, Rosella Caruso, Marco Casolino, Karel Černý, Mark J. Christl, Roberta Colalillo, Hank J. Crawford, Alexandre Creusot, Austin Cummings, Julia Desiato, Rebecca Diesing, Alessandro Di Nola, Toshikazu Ebisuzaki, Johannes Eser, Francesco Fenu, Silvia Ferrarese, George Filippatøs, William W. Finch, Flavia Flaminio, S. Flannery, Claudio Fornaro, Noah Friedlander, Duncan Fuehne, Christer Fuglesang, Srikar Gadamsetty, Diksha Garg, Eleanor Gazda, Alessio Golzio, Fausto Guarino, Claire Guépin, Tobias Heibges, Eleanor G. Judd, Luke Kupari, Pavel A. Klimov, John F. Krizmanic, Viktoria Kungel, Evgeny Kuznetsov, Marco Mignone, Massimiliano Manfrin, Wlodzimierz Marszał, John N. Matthews, Kameron Mehling, Marco Mese, Stephan S. Meyer, Hiroko Miyamoto, Alexey S. Murashov, Jane M. Nachtman, Angela V. Olinto, Yasar Onel, Giuseppe Osteria, A. Nepomuk Otte, Beatrice Panico, Etienne Parizot, Tom Paul, Miroslav Pech, Francesco Perfetto, Lech W. Piotrowski, Zbigniew Plebaniak, Jonatan Posligua, Matthew Potts, Guillaume Prévôt, M. Przybylak, Pat Reardon, Mary Hall Reno, Marco Ricci, Oscar F. Romero Matamala, Fred Sarazin, Petr Schovánek, Viktoria Scotti, Kenji Shinozaki, Jorge F. Soriano, S. Stephanoff, Patrick Sternberg, Ben K. Stillwell, Jacek Szabelski, Yoshiyuki Takizawa, Daniil Trofimov, Fredrik Unel, Valerio Vagelli, Laura Valore, Tonia M. Venters, John Watts Jr., Lawrence Wiencke, Hannah Wistrand, Roy YoungComments: 40 pages, 38 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) is a pathfinder mission toward a space-based observatory such as the Probe of Extreme Multi-Messenger Astrophysics (POEMMA). The aim of POEMMA is the observation of Ultra High Energy COsmic Rays (UHECRs) in order to elucidate their nature and origins and to discover $\gtrsim$ 20 PeV very high energy neutrinos that originate from transient and steady astrophysical sources. EUSO-SPB2 was launched from WÄnaka New Zealand on May 13th, 2023 as a NASA Balloon Program Office test flight. The mission goals included making the first near-space altitude observations of the fluorescence emission from UHECR-induced extensive air showers (EASs) and making the first direct Cherenkov light emission from PeV cosmic rays traversing Earth's atmosphere. In addition, a Target of Opportunity program was developed for selecting and scheduling observations of potential neutrino sources as they passed just below the Earth's limb. Although a leaky balloon forced termination over the Pacific Ocean after 37 hours, data was collected to demonstrate the successful commissioning and operation of the instruments. This paper includes a description of the payload and the key instruments, pre-flight instrument characterizations in the lab and in the desert, flight operations and examples of the data collected. The flight was too short to catch a UHECR event via fluorescence, however about 10 candidate EAS events from cosmic rays were recorded via Cherenkov light.
- [32] arXiv:2505.20821 [pdf, html, other]
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Title: A candidate for True Type-2 AGN without hidden central BLRs Identified by central Tidal Disruption EventComments: 15 pages, 7 figures; accepted by ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
In this manuscript, through applications of TDE (tidal disruption event) expected variability properties, a potential candidate for True type-2 AGN without hidden central broad line regions (=TT2AGN) is reported in the SDSS J233454.07+145712.9 (=SDSS J2334). Through analyzing the 20-years optical light curves of SDSS J2334 from different Sky Survey projects, a TDE is preferred with a $4.7{\rm M_\odot}$ main-sequence star tidally disrupted by the central BH with mass $11.7\times 10^6{\rm M_\odot}$, indicating that central region within distance about 20 light-days to central BH in SDSS J2334 is directly in the line-of-sight. Moreover, AGN activities in SDSS J2334 can be confirmed through applications of BPT diagrams. Meanwhile, comparing virial BH mass determined through assumed broad Balmer emission components and M-sigma expected BH mass by well measured stellar velocity dispersion through stellar absorption features, optical broad emission lines in SDSS J2334 are disfavored with confidence level higher than 6$\sigma$. Therefore, combining the unique properties of the TDE and the spectroscopic results with only narrow emission lines, SDSS J2334 can be well identified as a potential candidate for a TT2AGN. The results indicate the to detect TDE expected flares in normal Type-2 AGN classified by spectroscopic results should be a new practicable method for identifying
- [33] arXiv:2505.20842 [pdf, html, other]
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Title: TCP J07222683$+$6220548: a new AM CVn type system with infrequent outburstsAlexander Tarasenkov, Kirill Sokolovsky, Alexandr Dodin, Oxana Chernyshenko, Stanislav Korotkiy, Ivan Strakhov, Marina Burlak, Sergey Naroenkov, Franz-Josef Hambsch, Tamás Tordai, Hiroshi Itoh, Yasuo Sano, Yusuke Tampo, FerdinandComments: Accepted for publication in Research in Astronomy and AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present the discovery of TCP J07222683$+$6220548, a new ultracompact binary system of the AM CVn type. This system was first identified displaying a $\Delta V = 7.6$ mag outburst on 2025-01-20.9416 UTC by the New Milky Way wide-field survey for transients and later independently detected by ASAS-SN and ZTF. The outburst peaked at $V_{\rm max} = 12.45$ and lasted for seven days, followed by a series of rebrightenings. No previous outbursts are found in archival data. Positive superhumps with a period of $0.032546 \pm 0.000084$ d ($46.87 \pm 0.12$ min), barely detectable during the main outburst, became clearly visible during the first rebrightening that lasted from day 18 to day 24 after the initial outburst. No convincing change in the superhump period was detected. Dense time-series photometry follow-up by a pair of 0.5-m INASAN robotic telescopes, together with VSNET and AAVSO observers, was essential for identifying TCP J07222683$+$6220548 as an AM CVn system and triggering confirmation spectroscopy with the 2.5-m CMO SAI telescope. Some outbursting AM CVn systems lacking such detailed follow-up may remain unrecognized among the newly discovered cataclysmic variable candidates.
- [34] arXiv:2505.20947 [pdf, html, other]
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Title: Unified Deep Learning Approach for Estimating the Metallicities of RR Lyrae Stars Using light curves from Gaia Data Release 3Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Artificial Intelligence (cs.AI)
RR Lyrae stars (RRLs) are old pulsating variables widely used as metallicity tracers due to the correlation between their metal abundances and light curve morphology. With ESA Gaia DR3 providing light curves for about 270,000 RRLs, there is a pressing need for scalable methods to estimate their metallicities from photometric data. We introduce a unified deep learning framework that estimates metallicities for both fundamental-mode (RRab) and first-overtone (RRc) RRLs using Gaia G-band light curves. This approach extends our previous work on RRab stars to include RRc stars, aiming for high predictive accuracy and broad generalization across both pulsation types. The model is based on a Gated Recurrent Unit (GRU) neural network optimized for time-series extrinsic regression. Our pipeline includes preprocessing steps such as phase folding, smoothing, and sample weighting, and uses photometric metallicities from the literature as training targets. The architecture is designed to handle morphological differences between RRab and RRc light curves without requiring separate models. On held-out validation sets, our GRU model achieves strong performance: for RRab stars, MAE = 0.0565 dex, RMSE = 0.0765 dex, R^2 = 0.9401; for RRc stars, MAE = 0.0505 dex, RMSE = 0.0720 dex, R^2 = 0.9625. These results show the effectiveness of deep learning for large-scale photometric metallicity estimation and support its application to studies of stellar populations and Galactic structure.
- [35] arXiv:2505.20953 [pdf, html, other]
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Title: Comparing population synthesis models of compact double white dwarfs to electromagnetic observationsWouter G. J. van Zeist, Jan van Roestel, Gijs Nelemans, Jan J. Eldridge, Valeriya Korol, Silvia ToonenComments: 11 pages, 7 figures, 1 table. Accepted by A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Context: Studies of the Galactic population of double white dwarfs (DWDs) that would be detectable in gravitational waves by LISA have found differences in the number of predicted detectable DWDs of more than an order of magnitude, depending on the binary stellar evolution model used. Particularly, the binary population synthesis code BPASS predicts 20 to 40 times fewer detectable DWDs than the codes SeBa or BSE, which relates to differing treatments of mass transfer and common-envelope events (CEEs).
Aims: We aimed to investigate which of these models are closer to reality by comparing their predictions to the DWDs known from electromagnetic observations.
Methods: We compared the DWDs predicted by a BPASS galaxy model and a SeBa galaxy model to a DWD catalogue and the sample of DWDs observed by the Zwicky Transient Facility (ZTF), taking into account the observational limits and biases of the ZTF survey.
Results: We found that BPASS underpredicts the number of short-period DWDs by at least an order of magnitude compared to the observations, while the SeBa galaxy model is consistent with the observations for DWDs more distant than 500 pc. These results highlight how LISA's observations of DWDs will provide invaluable information on aspects of stellar evolution such as mass transfer and CEEs, which will allow theoretical models to be better constrained. - [36] arXiv:2505.20968 [pdf, html, other]
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Title: A numerical approach for modelling the polarisation signals of strong resonance lines with partial frequency redistribution. Numerical applications to two-term atoms and plane-parallel atmospheresFabio Riva, Gioele Janett, Luca Belluzzi, Tanausú del Pino Alemán, Ernest Alsina Ballester, Javier Trujillo Bueno, Pietro Benedusi, Simone Riva, Rolf KrauseSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Aims. The main goal of this paper is to present an accurate and efficient numerical strategy for solving the radiative transfer problem for polarised radiation in strong resonance lines forming out of local thermodynamic equilibrium, taking angle-dependent (AD) partial frequency redistribution (PRD) effects and J-state interference into account. We consider the polarisation produced both by the Zeeman effect and by the scattering of anisotropic radiation, along with its sensitivity to the Hanle and magneto-optical effects. Methods. We introduce a formalism that allows treating both a two-level and a two-term atom in the presence of arbitrary magnetic and bulk velocity fields. The problem is formulated by treating the population of the lower level/term as a fixed input parameter. This approach makes the problem linear with respect to the radiation field, enabling the application of efficient matrix-free preconditioned iterative methods for its solution. Additionally, the computation of the scattering emissivity in the comoving frame, together with a careful choice of the angular and spectral quadrature nodes, allow us to speed up the calculations by reducing the number of evaluations of the redistribution functions. Results. The proposed solution strategy is applied to synthesise the Stokes profiles of the Mg ii h&k doublet and the H i Ly-{\alpha} line in 1D semi-empirical models. The results demonstrate that the method is both fast and accurate. A comparison with calculations from HanleRT-TIC displays an overall good agreement, thereby validating our solution strategy. Moreover, for the wavelength-integrated polarisation profiles of the H i Ly-{\alpha} line, we find an excellent agreement between the results obtained including PRD effects in their general AD description and those obtained considering the angle-averaged simplifying approximation.
- [37] arXiv:2505.21042 [pdf, html, other]
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Title: What exactly did the Transformer learn from our physics data?Comments: 9 pages, 7 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)
Transformer networks excel in scientific applications. We explore two scenarios in ultra-high-energy cosmic ray simulations to examine what these network architectures learn. First, we investigate the trained positional encodings in air showers which are azimuthally symmetric. Second, we visualize the attention values assigned to cosmic particles originating from a galaxy catalog. In both cases, the Transformers learn plausible, physically meaningful features.
- [38] arXiv:2505.21047 [pdf, html, other]
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Title: Characteristics of acoustic-wave heating in simulations of the quiet Sun chromosphereComments: 10 pages, 8 figures, accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Understanding energy transfer through the chromosphere is paramount to solving the coronal heating problem. We investigated the energy dissipation of acoustic waves in the chromosphere of the quiet Sun using 3D radiative magnetohydrodynamic (rMHD) simulations. We analysed the characteristics of acoustic-wave heating and its dependence on height and magnetic field configuration. We find the typical heights where acoustic waves steepen into shocks and the frequencies and wavenumbers that most efficiently dissipate wave energy through this steepening. We combined a comprehensive large-scale analysis, spanning the entirety of the simulations for several solar hours, with a detailed view of an individual shock. We find that the flux of propagating acoustic waves correlates closely with viscous dissipation in the chromosphere above the temperature minimum. Acoustic waves with frequencies close to the acoustic cut-off frequency can efficiently heat the quiet Sun chromosphere at the plasma-$\beta$ = 1 interface and play an important role in the chromospheric energy balance.
- [39] arXiv:2505.21053 [pdf, other]
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Title: Proposal for the optical design of three robust and highly performing FPI systems for the European Solar TelescopeComments: 38 pages. Comments, additions (with possible co-authorship) are welcome. This proposal needs community feedbackSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
We describe a proposal for the optical design of three dual Fabry-Perot based narrowband filter systems for for the future European Solar Telescope (EST). These are intended to constitute the core elements of three imaging spectropolarimeters, foreseen to become amongst the most important science instruments for EST. The designs proposed here rely heavily on the heritage of CRISP and CHROMIS, developed for the Swedish 1-m Solar Telescope and described in detail in a companion paper (Scharmer et al. 2025, in prep.). The outstanding performance of these systems, and the simplicity of their designs, provide strong support of our proposal to build similar systems for EST. The design concepts involve i) minimising the FPI clear aperture diameter by means of numerical simulations based on constraints on Strehl and spectral resolution set by the EST Science Advisory Group (SAG); ii) a compact telecentric optical design with an optical path length of less than 4.7 m; iii) a straight-through optical system based on lenses and without any folding mirrors; iv) the combination of a high resolution etalon with high reflectivity and a low reflectivity, low resolution etalon, to mitigate the effects of cavity errors (Scharmer 2006, Scharmer et al. 2025); v) flexibility in terms of image scale by simple replacement of the last lens (the camera lens) of the FPI system. We propose to compensate for the focus curve of ESTs Pier Optical Path (POP) by focusing the camera lenses of the FPI systems. s.
The proposed systems should offer several advantages over other much more complex systems, including manufacture, alignment, stability, flexibility of changes of image scale, and costs. The underlying design concepts also make the proposed FPI systems robust and highly performing in terms of image quality, overall transmission, and fidelity of the spectral transmission profile. - [40] arXiv:2505.21105 [pdf, html, other]
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Title: Identifying Compton-thick AGNs with Machine learning algorithm in Chandra Deep Field-SouthRui Zhang, Xiaotong Guo, Qiusheng Gu, Guanwen Fang, Jun Xu, Hai-Cheng Feng, Yongyun Chen, Rui Li, Nan Ding, Hongtao WangComments: 12 pages, 6 figures, 2 Tables. Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
Compton-thick active galactic nuclei (CT-AGNs), which are defined by column density $\mathrm{N_H} \geqslant 1.5 \times 10^{24} \ \mathrm{cm}^{-2}$, emit feeble X-ray radiation, even undetectable by X-ray instruments. Despite this, the X-ray emissions from CT-AGNs are believed to be a substantial contributor to the cosmic X-ray background (CXB). According to synthesis models of AGNs, CT-AGNs are expected to make up a significant fraction of the AGN population, likely around 30% or more. However, only $\sim$11% of AGNs have been identified as CT-AGNs in the Chandra Deep Field-South (CDFS). To identify hitherto unknown CT-AGNs in the field, we used a Random Forest algorithm for identifying them. First, we build a secure classified subset of 210 AGNs to train and evaluate our algorithm. Our algorithm achieved an accuracy rate of 90% on the test set after training. Then, we applied our algorithm to an additional subset of 254 AGNs, successfully identifying 67 CT-AGNs within this group. This result significantly increased the fraction of CT-AGNs in the CDFS, which is closer to the theoretical predictions of the CXB. Finally, we compared the properties of host galaxies between CT-AGNs and non-CT-AGNs and found that the host galaxies of CT-AGNs exhibit higher levels of star formation activity.
- [41] arXiv:2505.21107 [pdf, html, other]
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Title: The MUSE view of ram pressure stripped galaxies in clusters: the GASP sampleBianca M. Poggianti (INAF-OaPD), Benedetta Vulcani, Neven Tomicic, Alessia Moretti, Marco Gullieuszik, Cecilia Bacchini, Jacopo Fritz, Koshy George, Myriam Gitti, Alessandro Ignesti, Augusto Lassen, Antonino Marasco, Mario Radovich, Paolo Serra, Rory Smith, Stephanie Tonnesen, Anna WolterComments: A&A in pressSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present the full sample of 76 galaxies in 39 galaxy cluster fields at z=0.04-0.07 observed with VLT/MUSE by the GASP survey. Most of them (64) were observed as possible ram pressure stripped galaxies (stripping candidates) based on optical B-band images, while the remaining 12 were a control sample of both star-forming and passive galaxies. Based on spatially resolved ionized gas and stellar kinematics, we assess the physical origin of the gas asymmetries and find that 89% of the stripping candidates are confirmed by the VLT/MUSE data. In addition, also 3 of the 4 star-forming galaxies in the control sample show signs of ram pressure. These control galaxies display a ring of unusual emission line ratios, which we see also in field galaxies, possibly originating from the interaction with a hotter surrounding medium. The stripped galaxies are classified into various classes corresponding to different degrees of stripping, from weakest stripping to strong and extreme (jellyfish galaxies) stripping, as well as truncated gas disks with gas left only in the galaxy center. Our results show that selecting cluster stripping candidates based on optical imaging yields a sample that is indeed largely dominated by galaxies affected by ram pressure at different stages and stripping strength, though some contamination is present, mostly by tidal processes. Strong ram pressure cases are found in galaxies over the whole range of stellar masses studied (10^9-10^11.5 Msun) both in low-mass and high-mass clusters (cluster velocity dispersions sigma = 500-1100 km/s). We examine the possible connection between the progressive stages of stripping, up to the phase of a truncated gas disk, and the subsequent complete stripping of gas. We discuss the incompleteness intrinsic to this and other methods of selection to obtain a complete census of ram pressure stripping in clusters.
- [42] arXiv:2505.21110 [pdf, html, other]
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Title: Effect of Magnetic Field on the Accretion Phase of Population III Star FormationComments: Accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We examine the impact of the magnetic field on Population III star formation by varying the magnetic field strength. We perform simulations with magnetic field strengths ranging from $10^{-20}$ G to $10^{-4}$ G, in addition to a model without a magnetic field. The simulations are run for $>1000-1400$ yr after the first protostar forms. In weak-field models, the surrounding disk fragments, forming multiple protostars, and the magnetic field is amplified by the orbital motion and rotation of these protostars. In the model without a magnetic field, frequent fragmentation occurs, and the most massive protostar reaches $\sim200 M_\odot$. However, in models with a magnetic field, once the magnetic field is amplified, the protostars merge to form a single massive protostar, and no further fragmentation occurs except in the model with the strongest magnetic field. Even after the formation of the single protostar, the magnetic field continues to amplify, leading to the formation of a thick disk supported by magnetic pressure and a global spiral pattern. In models with moderate or strong magnetic fields, a rotating disk can form, but fragmentation does not occur, and a strong magnetic field drives an outflow. However, the range of parameters for both disk formation and outflow driving is very narrow, making their appearance under realistic conditions unlikely. Given the weak magnetic field in the early universe, Population III stars are expected to form as single stars, surrounded by a thick disk with a spiral pattern. Thus, the magnetic field, regardless of its strength, plays a crucial role in Population III star formation.
- [43] arXiv:2505.21127 [pdf, html, other]
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Title: The TYPHOON Stellar Population Synthesis Survey. II. Pushing Full Spectral Fitting to the Limit in the Nearby Grand Design Barred Spiral M83Eva Sextl, Rolf-Peter Kudritzki, Fabio Bresolin, Kathryn Grasha, Hye-Jin Park, Qian-Hui Chen, Andrew J. Battisti, Mark Seibert, Barry F. Madore, Jeffrey A. RichComments: 25 pages, 21 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
We apply population synthesis techniques to analyze TYPHOON long slit spectra of the starburst barred spiral galaxy M83. The analysis covers a central square of 5 arcmin side length. We determine the spatial distribution of dust through the analysis of reddening and extinction, together with star formation rates, ages, and metallicities of young and old stellar populations. For the first time, a spatial one-to-one comparison of metallicities derived from full-spectral fitting techniques with those obtained from individual young stellar probes has been carried out. The comparison with blue supergiant stars, young massive star clusters, and super star clusters shows a high degree of concordance when wavelength coverage in the $B$-band is available. The metallicity of the young population is supersolar and does not show a radial metallicity gradient along the investigated part of the disk, in agreement with our chemical evolution model. However, a notable decrease in metallicity is observed in a tightly confined region at the galaxy center, coinciding with circumnuclear orbits. We attribute this to matter infall either from the circumgalactic medium or a dwarf galaxy interloper or, alternatively, to AGN-interrupted chemical evolution. We confirm the presence of a dust cavity with a diameter of 260~pc close to the galaxy center. Dust absorption and molecular CO emission are spatially well correlated. We find an anticorrelation between R$_V$, the ratio of dust attenuation to reddening, and the emission strength of molecular species present in photo-dissociation regions. We confirm our results by using alternative fitting algorithms and stellar libraries.
- [44] arXiv:2505.21142 [pdf, html, other]
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Title: Is the Fermi source 4FGL J1824.2+1231 a transitional millisecond pulsar?D. A. Zyuzin, A. V. Karpova, A. Yu. Kirichenko, Yu. A. Shibanov, I. F. Bikmaev, M. R. Gilfanov, E. N. Irtuganov, M. A. Gorbachev, M. V. Suslikov, R. Karimov, M. M. Veryazov, M. PereyraComments: 9 pages, 9 figures. Accepted for publication in A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Transitional millisecond pulsars (tMSPs) in tight binary systems represent an important evolutionary link between low-mass X-ray binaries and radio millisecond pulsars. To date, only three confirmed tMSPs and a few candidates have been discovered. Most of them are gamma-ray sources. For this reason, searching for multiwavelength counterparts to unassociated Fermi gamma-ray sources can help to find new tMSPs. Here we investigate whether the unassociated gamma-ray source 4FGL J1824.2+1231 belongs to the tMSP family. To find the counterpart to 4FGL J1824.2+1231, we used data from SRG/eROSITA and Swift X-ray catalogues, and from different optical catalogues. We also performed time-series photometric optical observations of the source with the 2.1-m telescope of the Observatorio Astronomico Nacional San Pedro Martir, the 1.5-m telescope of the Maidanak Astronomical Observatory and the 1.5-m Russian-Turkish telescope. In addition, we carried out optical spectroscopic observations with the Russian-Turkish telescope and used archival spectroscopic data obtained with the Gemini-North telescope. Within the position error ellipse of 4FGL J1824.2+1231, we found only one X-ray source which coincides with an optical object. We consider it as a likely multiwavelength counterpart to 4FGL J1824.2+1231. The source shows strong optical variability and significant proper motion. The latter strongly implies that this is a Galactic source. Double-peaked H and He emission lines are detected in its spectrum with a flat continuum, as often observed in accretion disks of compact binary systems. The X-ray spectrum is well fitted by a power law with the photon index 1.7. The derived intrinsic X-ray-to-gamma-ray flux ratio is about 0.2. If the X-ray/optical source is the true counterpart to 4FGL J1824.2+1231, then all its properties suggest that it is a tMSP in the subluminous disk state.
- [45] arXiv:2505.21155 [pdf, html, other]
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Title: Magnetic flux cancellation in a flux-emergence magnetohydrodynamics simulation of coronal hole eruptions and jetsComments: A&A, 2025, in pressSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We search for signatures of magnetic flux cancellation in a 3D resistive MHD flux-emergence simulation of coronal jets and eruptions in a coronal-hole-like environment. To do this, we analysed the output from a 3D MHD simulation of an emerging twisted horizontal flux tube from the convection zone into the solar atmosphere. The simulation considered the impact of neutral hydrogen on the magnetic induction equation, that is, it employed partially ionised plasma. Standard and blowout jets as well as eruptions were observed during the simulation. We observe clear evidence of magnetic flux cancellation in a short segment along the internal polarity-inversion line (iPIL) of the photospheric Bz during an extended period of the simulation characterised by eruptions and blowout jets. Converging magnetic footpoint motions at ~ 1 km/s carried sheared fields within the magnetic tails of the emerging flux tube towards the iPIL. These fields reconnect at the iPIL and generate concave-upward and slowly rising field lines causing a flux decrease that is associated with magnetic flux cancellation. We show evidence of magnetic flux cancellation in 3D MHD simulations of coronal hole eruptions and jets associated with an emerging twisted flux tube. The magnetic flux cancellation can be traced up to about 520 km above the photosphere and might contribute to the formation of pre-eruptive magnetic flux rope seeds. Although our results are consistent with several basic aspects of magnetic flux-cancellation observations associated with coronal jets, the observations nevertheless also suggest that cancellation involves much larger fractions of the available flux than our numerical simulation. We supply avenues to address this discrepancy in future work.
- [46] arXiv:2505.21215 [pdf, html, other]
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Title: Transfer learning for multifidelity simulation-based inference in cosmologyAlex A. Saoulis, Davide Piras, Niall Jeffrey, Alessio Spurio Mancini, Ana M. G. Ferreira, Benjamin JoachimiComments: 9+4 pages, 8+5 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Machine Learning (cs.LG)
Simulation-based inference (SBI) enables cosmological parameter estimation when closed-form likelihoods or models are unavailable. However, SBI relies on machine learning for neural compression and density estimation. This requires large training datasets which are prohibitively expensive for high-quality simulations. We overcome this limitation with multifidelity transfer learning, combining less expensive, lower-fidelity simulations with a limited number of high-fidelity simulations. We demonstrate our methodology on dark matter density maps from two separate simulation suites in the hydrodynamical CAMELS Multifield Dataset. Pre-training on dark-matter-only $N$-body simulations reduces the required number of high-fidelity hydrodynamical simulations by a factor between $8$ and $15$, depending on the model complexity, posterior dimensionality, and performance metrics used. By leveraging cheaper simulations, our approach enables performant and accurate inference on high-fidelity models while substantially reducing computational costs.
- [47] arXiv:2505.21220 [pdf, html, other]
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Title: Wavelet Flow For Extragalactic Foreground SimulationsComments: 19 pages, 7 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Machine Learning (cs.LG)
Extragalactic foregrounds in cosmic microwave background (CMB) observations are both a source of cosmological and astrophysical information and a nuisance to the CMB. Effective field-level modeling that captures their non-Gaussian statistical distributions is increasingly important for optimal information extraction, particularly given the precise and low-noise observations from current and upcoming experiments. We explore the use of Wavelet Flow (WF) models to tackle the novel task of modeling the field-level probability distributions of multi-component CMB secondaries. Specifically, we jointly train correlated CMB lensing convergence ($\kappa$) and cosmic infrared background (CIB) maps with a WF model and obtain a network that statistically recovers the input to high accuracy -- the trained network generates samples of $\kappa$ and CIB fields whose average power spectra are within a few percent of the inputs across all scales, and whose Minkowski functionals are similarly accurate compared to the inputs. Leveraging the multiscale architecture of these models, we fine-tune both the model parameters and the priors at each scale independently, optimizing performance across different resolutions. These results demonstrate that WF models can accurately simulate correlated components of CMB secondaries, supporting improved analysis of cosmological data. Our code and trained models can be found here (this https URL).
- [48] arXiv:2505.21256 [pdf, html, other]
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Title: What triggers type Ia supernovae: Prompt detonations from primordial black holes or companion stars?Comments: 5 pages + 9 supplemental material, accepted by PRD Letters, comments welcome!Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We set up and perform collision rate simulations between dark matter in the form of asteroid-mass primordial black holes (PBHs) and white dwarf stars. These encounters trigger prompt detonations and could be the key to solving the ignition mystery of type Ia supernovae. Our framework is flexible enough to cover the full range of progenitor white dwarf masses, host galaxy stellar masses, galactocentric radial offsets, and cosmic time. The rate distribution pattern is consistent with exhaustive literature observational determinations for a slightly extended log-normal PBH mass spectrum. Most strikingly, the so far unexplained brightness distribution comes out without finetuning. We find no severe contradictions, except that the inferred PBH mass scale is unpredicted from first principles.
- [49] arXiv:2505.21260 [pdf, html, other]
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Title: Dark-matter-induced transients over cosmic time: The role of star formation history profilesComments: Accepted by PRD, citation requests welcome!Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
The dark matter (DM) conundrum is one of the most intriguing due to its resistance in direct detection experiments. In recent years, attempts to identify non-gravitational signatures as the result of DM traversing or accumulating within stars have attracted a lot of attention. These calculations are usually evaluated at the order-of-magnitude level for stellar populations where the DM density is highest, such as galactic centers. However, if the signature implies the destruction of the host star, their population could have been diminished over a Hubble time in the most DM-dense regions, unless replenished by star formation. This circumstance exemplifies the need for galactic star formation history profiles when deriving DM-induced transient rates, in particular for predicting the host-offset distribution. Here, we combine theoretical and empirical scaling relations of galaxy structure, star formation, and stellar initial mass function to construct a simple and efficient framework that permits us to estimate the target population formation rate and mass function within galactocentric radial zones across galaxy stellar masses and cosmic time. In a companion paper, we apply the framework to the hypothesis that DM in the form of primordial black holes accounts for the ignition of normal type Ia supernovae when colliding with white dwarf stars.
- [50] arXiv:2505.21261 [pdf, html, other]
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Title: A machine learning-enabled search for binary black hole mergers in LIGO-Virgo-KAGRAs third observing runEthan Marx, William Benoit, Trevor Blodgett, Deep Chatterjee, Emma de Bruin, Steven Henderson, Katrine Kompanets, Siddharth Soni, Michael Coughlin, Philip Harris, Erik KatsavounidisSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We conduct a search for stellar-mass binary black hole mergers in gravitational-wave data collected by the LIGO detectors during the LIGO-Virgo-KAGRA (LVK) third observing run (O3). Our search uses a machine learning (ML) based method, Aframe, an alternative to traditional matched filtering search techniques. The O3 observing run has been analyzed by the LVK collaboration, producing GWTC-3, the most recent catalog installment which has been made publicly available in 2021. Various groups outside the LVK have re-analyzed O3 data using both traditional and ML-based approaches. Here, we identify 38 candidates with probability of astrophysical origin ($p_\mathrm{astro}$) greater than 0.5, which were previously reported in GWTC-3. This is comparable to the number of candidates reported by individual matched-filter searches. In addition, we compare Aframe candidates with catalogs from research groups outside of the LVK, identifying three candidates with $p_\mathrm{astro} > 0.5$. No previously un-reported candidates are identified by Aframe. This work demonstrates that Aframe, and ML based searches more generally, are useful companions to matched filtering pipelines.
- [51] arXiv:2505.21264 [pdf, html, other]
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Title: Rapid binary mass transfer: Circumbinary outflows and angular momentum lossesComments: 24 pages, 18 figures. Submitted to ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
High rates of stable mass transfer likely occur for some binary star systems, but the resulting flow of mass and angular momentum (AM) is unclear. We perform hydrodynamical simulations of a polytropic donor star and a point mass secondary to determine the mass, AM, and velocity of gas that escapes the system, and the dependence on binary parameters such as mass ratio. The simulations use an adiabatic equation of state and do not include any radiative cooling or irradiation of the outflow. Mass transfer is initiated by injecting heat into the stellar envelope, causing it to gradually inflate and overflow its Roche lobe. The transferred mass flows into an accretion disk, but soon begins to escape through the outer Lagrange point (L2), with a lesser amount escaping through the L3 point. This creates an equatorially concentrated circumbinary outflow with an opening angle of 10 to 30 degrees with a wind-like density profile $\rho \propto r^{-2}$. We find that the ratios of the specific AM of the outflowing gas over that of the L2 point are approximately {0.95, 0.9, 0.8, 0.65} for binary mass ratios $q$ (accretor/donor) of {0.25, 0.5, 1, 2}. The asymptotic radial velocity of the outflowing gas, in units of the binary orbital velocity, is approximately 0.1 to 0.2 for the same mass ratios, except for $q=0.25$ where it might be higher. This outflow, if ultimately unbound from the binary, may be a source of circumstellar material that will interact with ejecta from a subsequent supernova or stellar merger.
- [52] arXiv:2505.21270 [pdf, html, other]
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Title: Exoplanet Ephemerides Change Observations (ExoEcho). II. Transit timing variation analysis of Brown Dwarfs around Solar-type StarsComments: 13 pages, 8 figures, 4 tables. Accepted by ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Transit timing variation (TTV) is a useful tool for studying the orbital properties of transiting objects. However, few TTV studies have been done on transiting brown dwarfs (BDs) around solar-type stars. Here we study the long-term TTV of a population of close BD companions around solar-type stars using TESS data. We use the measured orbital period change rate to constrain the tidal interaction strength between the host star and the BD companion and put limits on the destruction timescale of these transiting BDs. However, we find no statistically significant evidence of orbital decay or expansion in our sample based on the current data. This may be due to either poor observational data or inherently weak tidal dissipation. We then perform simulations to investigate future observation strategies for detecting orbital decay of transiting BDs, which show NGTS-7A b, TOI-263~b and LP 261-75 b are the most promising targets in the next few years. Our study demonstrates the potential of TTV technique to probe the formation and evolution of close BD companions around solar-type stars.
- [53] arXiv:2505.21271 [pdf, html, other]
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Title: The mantle-inner core gravitational mode of oscillation in a strong magnetic field regimeComments: 19 pages, 4 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Geophysics (physics.geo-ph)
The mantle-inner core gravitational (MICG) mode is the free mode axial oscillation between the mantle and inner core sustained by the gravitational torque between their degree 2 order 2 density structures. Here, we investigate how the MICG mode is affected by oscillations of cylindrical surfaces in the fluid outer core in the form of Alfvén waves. The latter are triggered by oscillations of the tangent cylinder (TC) moving jointly with the inner core and propagate away from the rotation axis. We show that the MICG mode remains a distinct normal mode of oscillation of the core-mantle system only when the triggered Alfvén waves are attenuated before they traverse the width of the fluid core. For an internal magnetic field strength of a few mT, as we expect in Earth's core, Alfvén waves can readily traverse the width of the core, and the MICG mode is absorbed into the spectrum of torsional oscillation (TO) modes. The MICG period retains a dynamical influence, acting as a point of resonance for TO modes, and marking the transition from a TO mode in which the motion of the TC (including the inner core) is weakly impacted by gravitational coupling to one in which the oscillating motion of the TC is strongly restricted. Our results imply that the observed 6-year periodic signal in the length of day cannot be interpreted as the signature of the MICG mode and must instead be caused by TO modes, or more generally, by the propagation of Alfvén waves.
- [54] arXiv:2505.21273 [pdf, html, other]
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Title: Rotational equilibrium of C$_2$ in diffuse interstellar cloudsComments: Accepted for publication in Astronomy and AstrophysicsSubjects: Astrophysics of Galaxies (astro-ph.GA)
Context. Recent spectroscopic measurements have revealed absorption from higher rotational levels in C$_2$ than previous observations. These improvements are accompanied by the availability of updated radiative and collisional data. Aims. We revisit the density and radiation field intensity diagnostics provided by the observations of many rotational levels of inter- stellar C$_2$ and extensive molecular information. Methods. We built an excitation model of C2 without spatial structure, including levels up to J= 34 where updated radiative and collisional excitation data are introduced as well as excitation by chemical formation. Results. We confirm the importance of the recent collisional excitation rate coefficients of C$_2$ by molecular H$_2$. We show that the new higher level observations cannot be explained by the standard balance between collisional excitation and radiative transitions. We propose that chemical excitation at formation provides a plausible mechanism to explain the observed high excitation of C$_2$. In addition, it allows us to lift the degeneracy of the density over radiation field strength parameter in the excitation model. Conclusions. A 0D model remains limited and it is highly desirable to use a full Photon Dominated Region (PDR) model, which includes all excitation processes introduced here and full chemical and thermal balance.
- [55] arXiv:2505.21307 [pdf, html, other]
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Title: PRODIGE - envelope to disk with NOEMA: V. Low 12C/13C ratios for CH3OH and CH3CN in hot corinosL. A. Busch, J. E. Pineda, O. Sipilä, D. M. Segura-Cox, P. Caselli, M. J. Maureira, C. Gieser, T.-H. Hsieh, M. T. Valdivia-Mena, L. Bouscasse, Th. Henning, D. Semenov, A. Fuente, M. Tafalla, J. J. Miranzo-Pastor, L. Colzi, Y.-R. Chou, S. GuilloteauComments: Accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
The 12C/13C isotope ratio has been derived towards numerous cold clouds (20-50 K) and a couple protoplanetary disks and exoplanet atmospheres. However, direct measurements of this ratio in the warm gas (>100 K) around young low-mass protostars remain scarce, but are required to study its evolution during star and planet formation. We derived 12C/13C ratios from the isotopologues of the complex organic molecules (COMs) CH3OH and CH3CN in the warm gas towards seven Class 0/I protostellar systems to improve our understanding of the evolution of the 12C/13C ratios during star and planet formation. We used the data that were taken as part of the PRODIGE large program with the NOEMA at 1mm. The emission of CH3OH and CH3CN is spatially unresolved in the PRODIGE data (300au scale). Derived rotational temperatures exceed 100K, telling us that they trace the gas of the hot corino, where CH3CN probes hotter regions than CH3OH on average (290 K versus 180 K). The column density ratios between the 12C and 13C isotopologues, derived from LTE analysis, range from 4 to 30, thus, are significantly lower than the expected local ISM isotope ratio of about 68. Assuming that CH3CN and CH3OH may inherit the 12C/13C ratio from their precursor species, astrochemical models were conducted for the latter and compared with our observational results. We conclude that an enrichment in 13C in COMs at the earliest protostellar stages is likely inherited from the COMs' precursor species, whose 12C/13C ratios are set during the prestellar stage via isotopic exchange reactions. This also implies that low 12C/13C ratios observed at later evolutionary stages could at least partially be inherited. A final conclusion on 12C/13C ratios in protostellar environments requires improved observations to tackle current observational limitations and additional modelling efforts.
- [56] arXiv:2505.21328 [pdf, html, other]
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Title: robostrategy: Field and Target Assignment Optimization in the Sloan Digital Sky Survey VMichael R. Blanton, Joleen K. Carlberg, Tom Dwelly, Ilija Medan, S. Drew Chojnowski, Kevin Covey, Megan C. Davis, John Donor, Pramod Gupta, Alexander Ji, Jennifer A. Johnson, Juna A. Kollmeier, Jose Sanchez-Gallego, Conor Sayres, Eleonora ZariComments: 45 pages, 14 figures, submitted to the Astronomical JournalSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present an algorithmic method for efficiently planning a long-term, large-scale multi-object spectroscopy program. The Sloan Digital Sky Survey V (SDSS-V) Focal Plane System performs multi-object spectroscopy using 500 robotic positioners to place fibers feeding optical and infrared spectrographs across a wide field. SDSS-V uses this system to observe targets throughout the year at two observatories in support of the science goals of its Milky Way Mapper and Black Hole Mapper programs. These science goals require observations of objects over time with preferred temporal spacinges (referred to as "cadences"), which can differ from object to object even in the same area of sky. robostrategy is the software we use to construct our planned observations so that they can best achieve the desired goals given the time available as a function of sky brightness and local sidereal time, and to assign fibers to targets during specific observations. We use linear programming techniques to seek optimal allocations of time under the constraints given. We present the methods and example results obtained with this software.
- [57] arXiv:2505.21352 [pdf, html, other]
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Title: Discovery of a kinematically distinct component in the central region of the collisional ring galaxy AM0644-741Comments: Accepted for publication in A&A LettersSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present the discovery of a peculiar central stellar structure in the collisional ring galaxy AM0644-741 using HST imaging and MUSE integral field unit (IFU) data. We identified two Sérsic components with a Sérsic index of 1.72 (inner part) and 1.11 (outer part) in the HST F814W band optical image using \textsc{Galfit}. We utilized the MUSE data cube to construct stellar line of sight velocity (V$_{\rm LOS}$), velocity dispersion ($\sigma_{\rm LOS}$), h$_3$ \& h$_4$ velocity moments, and stellar population age maps using the \textsc{GIST} pipeline for further investigating both Sérsic components, which have a difference of $\sim$ 60 degrees in their position angle. The inner component, with an effective radius $\sim$1 kpc, shows a strong anticorrelation between V$_{\rm LOS}$/$\sigma_{\rm LOS}$ and h$_3$, indicating the presence of a rotating stellar structure. In addition, the inner component also shows a relatively higher velocity dispersion (average values reaching up to $\sim$240 km sec$^{-1}$) along with disky isophotes and stronger Mg~$b$ line strength, which all together highlight a peculiar dynamical state of AM0644-741's central region. Our analysis suggests that the recent encounter has had a smaller impact on the stellar orbits within the inner component. In contrast, it has specifically affected the stellar orbits of the progenitor's outer disk when forming the star-forming ring. The BPT analysis of the unresolved nuclear source shows a LINER-type ionization, hinting at AGN activity in the galaxy. Our study projects the dynamical evolution of collisional systems and provides scope for simulations to explore the central region in greater detail.
- [58] arXiv:2505.21358 [pdf, html, other]
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Title: The James Webb Space Telescope NIRSpec-PRISM Transmission Spectrum of the Super-Puff, Kepler-51dJessica E. Libby-Roberts, Aaron Bello-Arufe, Zachory K. Berta-Thompson, Caleb I. Cañas, Yayaati Chachan, Renyu Hu, Yui Kawashima, Catriona Murray, Kazumasa Ohno, Armen Tokadjian, Suvrath Mahadevan, Kento Masuda, Leslie Hebb, Caroline Morley, Guangwei Fu, Peter Gao, Kevin B. StevensonComments: 34 pages, 13 figures, submitted to AJSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Kepler-51 is a 500 Myr G dwarf hosting three "super-puffs" and one low-mass non-transiting planet. Kepler-51d, the coolest (T_eq ~ 350 K) transiting planet in this system, is also one of the lowest density super-puffs known to date (rho_p = 0.038 +/- 0.009 g/cm^3). With a planetary mass of Mp = 5.6 +/- 1.2 Earth masses and a radius of Rp = 9.32 +/- 0.18 Earth radii, the observed properties of this planet are not readily explained by most planet formation theories. Hypotheses explaining Kepler-51d's low density range from a substantial H/He envelope comprising more than 30% of its mass, to a high-altitude haze layer, to a tilted ring system. To test these hypotheses, we present the NIRSpec-PRISM 0.6-5.3 micron transmission spectrum of Kepler-51d observed by the James Webb Space Telescope. We find a spectrum best fit by a sloped line covering the entire wavelength range. Based on forward modeling and atmosphere retrievals, Kepler-51d likely possesses a low-metallicity atmosphere with high-altitude hazes of submicron particle sizes spanning pressures of 1-100 microbars. However, the spectrum could also be explained by a tilted ring with an estimated lifetime on the order of ~0.1 Myr. We also investigate the stellar activity of this young Sun-like star, extracting a spot temperature significantly hotter than sunspots and spot covering fractions on the order of 0.1-10%, depending on the assumed spot parameters.
- [59] arXiv:2505.21368 [pdf, html, other]
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Title: Classifying the derivatives of light curves for overcontact eclipsing binariesComments: 8 pages, 5 figures, accepted for publication in PASJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Recent studies indicate that the physical properties of eclipsing binaries can be extracted from the derivatives of their light curves. A classification scheme for the derivatives of light curves would be helpful for identifying key characteristics of eclipsing binaries. In this study, we propose a new classification method for the light curves of overcontact eclipsing binaries by using their derivatives. We synthesized 89,670 sample light curves of overcontact binaries and categorized them into five types on the basis of their first to fourth derivatives. For each type, we examined the statistical distributions of four parameters: the mass ratio, orbital inclination, fill-out factor, and eclipse obscuration. Their distributions demonstrated that parameter values exhibit certain trends depending on the classified types. With the proposed classification method, general properties of overcontact binaries can be understood, providing a foundation for further detailed analysis.
- [60] arXiv:2505.21383 [pdf, html, other]
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Title: Gravitational waves of quasi-circular, inspiraling black hole binaries in an ultralight vector dark-matter environmentComments: 15 pages, 6 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
The gravitational waves emitted by massive black hole binaries can be affected by a variety of environmental effects, which, if detected, could inform astrophysics and cosmology. We here study how gravitational waves emitted by black holes in quasi-circular orbits are affected by the presence of an ultra-light, vector-field, dark-matter environment that is minimally coupled to the binary. This dark-matter environment induces oscillatory gravitational potentials that perturb the orbit of the binary, leaving an imprint in the binary's binding energy, and thus, on the gravitational waves emitted. We here compute the effect of this environment on the gravitational-wave phase using the stationary-phase approximation within the post-Newtonian formalism. We then perform a Fisher analysis to estimate the detectability of this environmental effect with a four-year LISA observation, focusing on vector fields with ultra-light masses in the $(10^{-19}, 10^{-16}) \; \rm{eV}$ range. We conclude that the observation of such gravitational waves with space-borne interferometers, like LISA, could yield a measurement or constraint on local, vector dark-matter environments, provided the dark-matter density is larger than roughly $10^{14} \rm{M}_\odot/{\rm{pc}}^3$.
- [61] arXiv:2505.21392 [pdf, html, other]
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Title: Kilonova modelling and parameter inference: Understanding uncertainties and evaluating compatibility between observations and modelsThomas Hussenot-Desenonges (1), Marion Pillas (2), Sarah Antier (1 and 3), Patrice Hello (1), Peter T. H. Pang (4 and 5) ((1) Université Paris-Saclay, CNRS/IN2P3, IJCLab, (2) STAR institute Université de Liège, (3) Observatoire de la Côte d'Azur, (4) Nikhef, (5) Institute for Gravitational and Subatomic Physics (GRASP), Utrecht University)Comments: 23 pages, 16 figures, 6 tables (1 sidewaystable)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
In the study of optical transients, parameter inference is the process of extracting physical information, i.e. constraints on the source's characteristics, by comparing the observed lightcurves to the predictions of different models and finding the model and parameter combination that make the closest match. In the developing field of the study of kilonovae (KNe), systematic uncertainties in modelling are still very large, and many models struggle to fit satisfactorily the whole multi-wavelength dataset of the AT2017gfo kilonova, associated to the Binary Neutron Star (BNS) merger GW170817. In a multi-messenger context, we sometime observe tensions between KN-only inference results and constraints from other messengers. In order to discuss the compatibility of KN models with observations and with the information derived from other messengers, we detail the process of Bayesian parameter inference, identifying the many sources of uncertainty embedded in KN analyses. We highlight the systematic error margin hyperparameter $\sigma_{\rm sys}$, which can be exploited as a metric for a model's goodness-of-fit. We then discuss how to assess the performance of parameter inference analyses by quantifying the information gain using the Kullback-Leibler divergence between prior and posterior. Using the example of the Bu2019lm model with the NMMA Bayesian inference framework, we showcase the expected performance that dedicated KN follow-ups with telescope networks could reasonably reach, highlighting the different factors (observational cadence, error margins) that influence such inference performances. We finally apply our KN analysis to the dataset of AT2017gfo to validate our performance predictions and discuss the complementarity of multi-messenger approaches.
- [62] arXiv:2505.21431 [pdf, html, other]
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Title: Non-minimal light-curvature couplings and black-hole imagingComments: 14 pages; 5 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Non-minimal couplings between the electromagnetic field strength and the spacetime curvature are part of the effective field theory of gravity and matter. They alter the local propagation of light in a significant way if the ratio of spacetime curvature to the non-minimal coupling is of order one. Spacetime curvature can become appreciable around black holes, and yet the effect of non-minimal couplings on electromagnetic observations of black holes remains underexplored. A particular feature of the non-minimal coupling between the electromagnetic field-strength and the Riemann tensor is that it generates two distinct photon rings for different polarizations. Working within the paradigm of lensing bands, and focusing on the $n=1$ photon ring, we investigate which values of the non-minimal coupling can be robustly excluded.
- [63] arXiv:2505.21463 [pdf, html, other]
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Title: Spectral Evolution of Rotating Population III StarsComments: 18 pages, 6 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Population III (Pop III) stars, the first generation of stars formed from primordial gas, played a fundamental role in shaping the early universe through their influence on cosmic reionization, early chemical enrichment, and the formation of the first galaxies. However, to date they have eluded direct detection due to their short lifetimes and high redshifts. The launch of the James Webb Space Telescope (JWST) has revolutionized observational capabilities, providing the opportunity to detect Pop~III stars via caustic lensing, where strong gravitational lensing magnifies individual stars to observable levels. This prospect makes it compelling to develop accurate models for their spectral characteristics to distinguish them from other stellar populations. Previous studies have focused on computing the spectral properties of non-rotating, zero-age main sequence (ZAMS) Pop III stars. In this work, we expand upon these efforts by incorporating the effects of stellar rotation and post-ZAMS evolution into spectral calculations. We use the JWST bands and magnitude limits to identify the optimal observing conditions, both for isolated stars, as well as for small star clusters. We find that, while rotation does not appreciably change the observability at ZAMS, the subsequent evolution can significantly brighten the stars, making the most massive ones potentially visible with only moderate lensing.
- [64] arXiv:2505.21470 [pdf, html, other]
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Title: Changing disc compositions via internal photoevaporation II: M dwarf systemsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The chemical evolution of the inner regions of protoplanetary discs is a complex process. Several factors influence it, one being the inward drift and evaporation of volatile-rich pebbles. During the disc's evolution, its inner part is first enriched with evaporating water-ice, resulting in a low C/O ratio. Afterwards, C-rich gas from the outer disc is transported inwards. Consequently, the C/O ratio of the inner disc increases again after 2 Myr. Previously, we studied how internal photoevaporation influences these processes in discs around Sun-like stars. We now extend our study to lower-mass stars, where the time evolution of the disc's C/O ratio is different due to the closer-in position of the evaporation fronts and differences in disc mass, size and structure. Our simulations are carried out with the semi-analytical 1D disc model chemcomp, which includes viscous evolution and heating, pebble growth and drift, pebble evaporation and condensation, as well as a simple chemical partitioning model. We show that internal photoevaporation plays a major role in the evolution of protoplanetary discs: As for Sun-like stars, photoevaporation opens a gap, which stops inward drifting pebbles. In addition, volatile-rich gas from the outer disc is carried away by the photoevaporative winds. Consequently, the C/O ratio in the inner disc remains low, contradicting observations of discs around low-mass stars. Our model implies that young inner discs (< 2 Myr) should be O-rich and C-poor, while older discs (> 2 Myr) should be C-rich. The survival of discs to this age can be attributed to lower photoevaporation rates, which either originate from a large spread of observed X-ray luminosities or from the photoevaporation model used here, which likely overestimates the photoevaporation efficiency. A reduction of the latter brings the calculated elemental abundances into better agreement with observations.
- [65] arXiv:2505.21474 [pdf, html, other]
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Title: INTEGRAL/ISGRI post 2024-periastron view of PSR B1259-63Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
PSR B1259-63/LS 2883 is a well-studied gamma-ray binary hosting a pulsar in a 3.4-year eccentric orbit around a Be-type star. Its non-thermal emission spans from radio to TeV energies, exhibiting a significant increase near the periastron passage. This paper is dedicated to the analysis of INTEGRAL observations of the system following its last periastron passage in June 2024. We aim to study the spectral evolution of this gamma-ray binary in the soft (0.3-10 keV) and hard (30-300 keV) X-ray energy bands. We performed a joint analysis of the data taken by INTEGRAL/ISGRI in July-August 2024 and quasi-simultaneous Swift/XRT observations. The spectrum of the system in the 0.3-300 keV band is well described by an absorbed power law with a photon index of $\Gamma=1.42\pm 0.03$. We place constraints on potential spectral curvature, limiting the break energy $E_\mathrm{b}>30$ keV for $\Delta\Gamma>0.3$ and cutoff energy $E_\mathrm{cutoff}>150$ keV at 95% confidence level. For one-zone leptonic emission models, these values correspond to electron distribution spectral parameters of $E_\mathrm{b,e}>0.8$ TeV and $E_\mathrm{cutoff,e}>1.7$ TeV, consistent with previous constraints derived by H.E.S.S.
- [66] arXiv:2505.21492 [pdf, html, other]
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Title: Dust removal timescale in galaxies across cosmic timeComments: submitted to A&A, under reviewSubjects: Astrophysics of Galaxies (astro-ph.GA)
Understanding the evolution of dust in galaxies is crucial because it affects the dynamics and cooling of gas, star formation, and chemical evolution. Recent work on dust removal in galaxies indicates timescales of gigayears, with old stellar populations and AGNs as the primary drivers of this process. However, most statistically significant studies are focused on low redshifts $z < 0.4$. Here, we determine the dust removal timescale in galaxies over a wide range of redshifts, up to $z \sim 5$. We use publicly available catalogue data of infrared-selected galaxies, observed by \textit{Herschel}. Using the inferred dust masses, stellar masses, and stellar ages, we calculate the dust removal timescale in a sample of more than 120,000 galaxies. We find that, with increasing redshift, the dust removal timescale decreases from 1.8 Gyr at redshift $z \sim 0.05$ to less than 500\,Myr at $z > 3$. Galaxies at higher redshifts undergo more efficient dust removal than galaxies at lower redshift, likely driven by AGN activity, supernova shocks, and astration. These findings indicate that dust removal evolves over cosmic time, reflecting the changing mechanisms regulating dust content of galaxies as the Universe evolves.
New submissions (showing 66 of 66 entries)
- [67] arXiv:2505.20317 (cross-list from physics.ins-det) [pdf, html, other]
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Title: Measurement of cosmic muon-induced events in an HPGe detector using time-coincidence techniqueSubjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); Nuclear Experiment (nucl-ex)
Detailed understanding and suppression of backgrounds are among the key challenges faced by Coherent Elastic Neutrino-Nucleus Scattering (CE\ensuremath{\nu}NS) experiments. The sensitivity of these experiments is largely determined by the background levels arising from various sources. Above-ground and shallow-overburden neutrino experiments typically employ passive shielding, primarily composed of lead (Pb), to suppress environmental $\gamma$ background. However, such shielding can introduce additional backgrounds that are particularly challenging for CE\ensuremath{\nu}NS experiments. These backgrounds arise mainly from $\gamma$ and neutrons produced by cosmic muon interactions in the shielding, and their contribution can become significant depending on the amount of Pb shielding used. In the current work, we measure the yield of secondary particles originating from Pb as a result of high-energy cosmic muon interaction, using a high-purity germanium (HPGe) detector and plastic scintillators. A time-coincidence technique is used to identify and reject these secondary background events from the experimental data. The obtained mean characteristic time of these residual background events is 11 $\pm$ 4 $\mu$s, which is consistent with the Geant4-based MC simulation result of 11 $\pm$ 1 $\mu$s. The measured efficiency-corrected rate of muon-induced events in the HPGe detector is 34 $\pm$ 1 (stat.) $\pm$ 3 (sys.) day$^{-1}$kg$^{-1}$ within the energy range of 30 keV to 2000 keV. The yield of muon-induced secondary backgrounds in 10 cm thick Pb shielding is evaluated to be $(11 \pm 1 (\text{stat.}) \pm 1 (\text{sys.}))$ secondary events$\thinspace\text{kg}^{-1}\thinspace\mathrm{m^{-2}}\thinspace\text{muon}^{-1}$ at sea level.
- [68] arXiv:2505.20386 (cross-list from hep-ph) [pdf, html, other]
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Title: Precision Unitarity Calculations in Inflationary ModelsComments: 39 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We revisit perturbative unitarity in scalar field inflation with a nonminimal coupling, with Higgs inflation serving as the most prominent example. Although such models are phenomenologically successful, it is critical to examine whether or not unitarity violations spoil their theoretical self-consistency. The analysis of these issues has so far typically relied on order-of-magnitude estimates of scattering amplitudes, which are appropriate for generic parameters. It is not evident that these methods apply to scenarios relying on a near-critical inflationary potential, for which an interplay of both small scalar self-couplings and nonminimal couplings could partially alleviate the unitarity issues. To allow for an exploration of this possibility, we consider the full $S$-matrix for the relevant scattering processes, taking into account important phase space volume factors, leading to a precise evaluation of the cut-off scale. In the single-field case, we demonstrate that near-criticality raises the cut-off scale considerably, compared to previous estimates. In the multifield case, momentum-dependent self-interactions in the kinetic sector lower the cut-off compared to the single-field case to a value comparable to but slightly larger than previous estimates. We carefully study both the single-field and multifield cases in metric and metric-affine (Palatini) formulations of gravity, as well as introduce a new phenomenologically viable model with a canonical kinetic term and a significantly raised cut-off, and discuss the importance of background field effects.
- [69] arXiv:2505.20389 (cross-list from hep-ph) [pdf, html, other]
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Title: Dispersion relation of the neutrino plasma: Unifying fast, slow, and collisional instabilitiesComments: 43 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
In neutrino-dense astrophysical environments, these particles exchange flavor through a coherent weak field, forming a collisionless neutrino plasma with collective flavor dynamics. Instabilities, which grow and affect the environment, may arise from neutrino-neutrino refraction alone (fast limit), vacuum energy splittings caused by masses (slow limit), or neutrino-matter scattering (collisional limit). We present a comprehensive analytical description of the dispersion relation governing these unstable modes. Treating vacuum energy splittings and collision rates as small perturbations, we construct a unified framework for fast, slow, and collisional instabilities. We classify modes into gapped, where collective excitations are already present in the fast limit but rendered unstable by slow or collisional effects, and gapless, which are purely generated by these effects. For each class, we derive approximate dispersion relations for generic energy and angle distributions, which reveal the order of magnitude of the growth rates and the nature of the instabilities without solving directly the dispersion relation. This approach confirms that slow and collisionally unstable waves generally grow much more slowly than they oscillate. Consequently, the common fast-mode approximation of local evolution within small boxes is unjustified. Even for fast modes, neglecting large-distance propagation of growing waves, as usually done, may be a poor approximation. Our unified framework provides an intuitive understanding of the linear phase of flavor evolution across all regimes and paves the way for a quasi-linear treatment of the instability's nonlinear development.
- [70] arXiv:2505.20402 (cross-list from gr-qc) [pdf, html, other]
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Title: Probing supermassive black hole scalarization with Pulsar Timing ArraysComments: 23 pages, 9 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
Scalar-tensor theories with a scalar field coupled to the Gauss-Bonnet invariant can evade no-hair theorems and allow for non-trivial scalar profiles around black holes. This coupling is characterized by a length scale $\lambda$, which, in an effective field theory perspective, sets the threshold below which deviations from General Relativity become significant. LIGO/VIRGO constraints indicate $\lambda$ is small, implying supermassive black holes should not scalarize. However, recent work suggests that scalarization can occur within a narrow window of masses, allowing supermassive black holes to scalarize, while leaving LIGO/VIRGO sources unaffected. We explore the impact of this scenario on the stochastic gravitational wave background recently observed by Pulsar Timing Arrays. We find that scalarization can alter the characteristic strain produced by circularly inspiralling SMBH binaries and that current data shows a marginal preference for a non-zero $\lambda$. However, similar signatures could arise from astrophysical effects such as orbital eccentricity or environmental interactions, emphasizing the need for improved modeling and longer observations to discriminate among the different scenarios.
- [71] arXiv:2505.20450 (cross-list from hep-ph) [pdf, html, other]
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Title: Searching for Axion Dark Matter Near Relaxing MagnetarsComments: 38 pages, 13 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
Axion dark matter passing through the magnetospheres of magnetars can undergo hyper-efficient resonant mixing with low-energy photons, leading to the production of narrow spectral lines that could be detectable on Earth. Since this is a resonant process triggered by the spatial variation in the photon dispersion relation, the luminosity and spectral properties of the emission are highly sensitive to the charge and current densities permeating the magnetosphere. To date, a majority of the studies investigating this phenomenon have assumed a perfectly dipolar magnetic field structure with a near-field plasma distribution fixed to the minimal charge-separated force-free configuration. While this {may} be a reasonable treatment for the closed field lines of conventional radio pulsars, the strong magnetic fields around magnetars are believed to host processes that drive strong deviations from this minimal configuration. In this work, we study how realistic magnetar magnetospheres impact the electromagnetic emission produced from axion dark matter. Specifically, we construct charge and current distributions that are consistent with magnetar observations, and use these to recompute the prospective sensitivity of radio and sub-mm telescopes to axion dark matter. We demonstrate that the two leading models yield vastly different predictions for the frequency and amplitude of the spectral line, indicating systematic uncertainties in the plasma structure are significant. Finally, we discuss various observational signatures that can be used to differentiate the local plasma loading mechanism of an individual magnetar, which will be necessary if there is hope of using such objects to search for axions.
- [72] arXiv:2505.20538 (cross-list from cs.CL) [pdf, other]
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Title: AstroVisBench: A Code Benchmark for Scientific Computing and Visualization in AstronomySebastian Antony Joseph, Syed Murtaza Husain, Stella S. R. Offner, Stéphanie Juneau, Paul Torrey, Adam S. Bolton, Juan P. Farias, Niall Gaffney, Greg Durrett, Junyi Jessy LiSubjects: Computation and Language (cs.CL); Instrumentation and Methods for Astrophysics (astro-ph.IM); Machine Learning (cs.LG)
Large Language Models (LLMs) are being explored for applications in scientific research, including their capabilities to synthesize literature, answer research questions, generate research ideas, and even conduct computational experiments. Ultimately, our goal is for these to help scientists derive novel scientific insights. In many areas of science, such insights often arise from processing and visualizing data to understand its patterns. However, evaluating whether an LLM-mediated scientific workflow produces outputs conveying the correct scientific insights is challenging to evaluate and has not been addressed in past work. We introduce AstroVisBench, the first benchmark for both scientific computing and visualization in the astronomy domain. AstroVisBench judges a language model's ability to both (1) create astronomy-specific workflows to process and analyze data and (2) visualize the results of these workflows through complex plots. Our evaluation of visualizations uses a novel LLM-as-a-judge workflow, which is validated against annotation by five professional astronomers. Using AstroVisBench we present an evaluation of state-of-the-art language models, showing a significant gap in their ability to engage in astronomy research as useful assistants. This evaluation provides a strong end-to-end evaluation for AI scientists that offers a path forward for the development of visualization-based workflows, which are central to a broad range of domains from physics to biology.
- [73] arXiv:2505.20545 (cross-list from gr-qc) [pdf, html, other]
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Title: Exploring the Structural Properties of Anisotropic Dark Matter-Admixed Quark StarsComments: 14 pages, 3 figures, accepted for publication in the journal Physics of the Dark UniverseSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Phenomenology (hep-ph)
We investigate anisotropic compact stars comprising two non-interacting fluids: quark matter and condensed dark matter. Using the MIT Bag model equation of state for quark matter and Bose-Einstein Condensate equation of state for dark matter, we numerically compute interior solutions for those two-fluid component spherical configurations. Varying the initial central density ratio of dark matter to quark matter, we examine how different proportions of these components influence the mass-radius profile, the factor of compactness as well as the quark mass fraction. Recent studies suggest that quark matter may exist in the cores of massive neutron stars, significantly affecting their structure and stability. We calculate the factor of compactness for both negative and positive anisotropy cases explored in this article. Our findings demonstrate that dark matter-admixed quark stars are more compact yet less massive compared to pure quark matter stars, aligning with recent theoretical predictions and gravitational wave observations.
- [74] arXiv:2505.20586 (cross-list from gr-qc) [pdf, html, other]
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Title: Strong coupling and instabilities in singularity-free inflation from an infinite sum of curvature correctionsComments: 13 pages, no figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
Four-dimensional gravitational theories derived from an infinite sum of Lovelock curvature invariants, combined with a conformal rescaling of the metric, are equivalent to a subclass of shift-symmetric Horndeski theories that possess a single scalar degree of freedom. Under the assumption of a homogeneous and isotropic cosmological background, the theory admits an inflationary solution that replaces the Big Bang singularity. This can be achieved by a solution where the Hubble expansion rate $H$ is equal to the time derivative of the scalar field $\dot{\phi}$. We show that the solution $H=\dot{\phi}$ suffers from a strong coupling problem, characterized by the vanishing kinetic term of linear scalar perturbations at all times. Consequently, nonlinear scalar perturbations remain uncontrolled from the onset of inflation throughout the subsequent cosmological evolution. Moreover, tensor perturbations are generally subject to Laplacian instabilities during inflation. This instability in the tensor sector also persists under background initial conditions where $H \neq \dot{\phi}$. In the latter case, both the coefficient of the kinetic term for scalar perturbations and the scalar sound speed diverge at the onset of inflation. Thus, the dominance of inhomogeneities in this theory renders the homogeneous background solution illegitimate.
- [75] arXiv:2505.20595 (cross-list from quant-ph) [pdf, html, other]
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Title: Inflationary power spectrum from the Lanczos algorithmComments: 9 pages, 5 figuresSubjects: Quantum Physics (quant-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
The generalized Lanczos algorithm can provide a universal method for constructing the wave function under the group structure of Hamiltonian. Based on this fact, we obtain an open two-mode squeezed state as the quantum origin for the curvature perturbation. In light of this wave function in the open system, we successfully develop a new method to calculate its corresponding power spectrum by using the Bogoliubov transformation. Unlike traditional approaches, we explicitly retain the Bogoliubov coefficients in terms of the squeezing amplitude \( r_k \) and the squeezing rotation angle \( \phi_k \). As a result, the power spectrum of the open two-mode squeezed state will match that of the Bunch-Davies vacuum numerically. Furthermore, the derivation of the open two-mode squeezed state relies on the second kind Meixner polynomial (equivalent to the generalized Lanczos algorithm) and the symmetry of the Hamiltonian. Therefore, our research may offer a new insight into the calculation of the correlation functions through a group-theoretic perspective.
- [76] arXiv:2505.20736 (cross-list from gr-qc) [pdf, html, other]
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Title: Characteristic precessions of spherical orbit around a rotating braneworld black holeComments: 13 pages, 5 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
We study the orbital dynamics and relativistic precession effects in the spacetime of rotating braneworld black holes within the Randall-Sundrum framework. For test particles on spherical orbits, we analyze three conserved quantities-energy, angular momentum, and Carter constant-and examine how the innermost stable spherical orbit depends on the tidal charge and orbital inclination. Compared to Kerr black holes, braneworld corrections significantly modify both nodal and periastron precession frequencies: positive tidal charges suppress precession rates, while negative charges enhance them. For stationary gyroscopes, we calculate the Lense-Thirring precession frequency and demonstrate its sensitivity to the tidal charge, black hole spin, and gyroscope orientation. Our results show that a positive tidal charge weakens frame-dragging effects even as it enhances gravitational attraction-offering a distinctive signature of extra-dimensional gravity. These results have important implications for astrophysical observations, including accretion disk behavior, stellar orbital dynamics, and gravitational wave detection. The modified orbital and gyroscopic precession provide new ways to test braneworld gravity in strong-field regimes.
- [77] arXiv:2505.20990 (cross-list from nucl-th) [pdf, html, other]
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Title: Fully general relativistic description of rapidly-rotating axially-symmetric neutron stars for constraining nuclear matter equations of stateComments: 13 pages, 7 figures, 6 tablesSubjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
Background: Constraining the nuclear matter equation of state (EoS) from neutron star observations is one of the main subjects in nuclear physics today. In general, neutron stars rotate rapidly and structure of neutron stars can be affected, especially in millisecond pulsars. To better constrain the nuclear EoS, it is important to describe neutron star structure taking into account the effects of rotation in a fully relativistic manner. Purpose: In this study, we investigate the internal structure of neutron stars under the influence of rotation. We explore correlations between rotational effects and EoS parameters, based on realistic calculations of rapidly rotating neutron stars based on the KEH method, which provides stable solutions for axially symmetric rotating equilibrium configurations. Results: Using 5 different Skyrme EoS parameter sets, we find that the maximum angular frequency achievable by rotating neutron stars, as calculated via the KEH method, varies depending on the stiffness of the equation of state. We confirm that an increase in the rotating frequency leads to an overall increase in both the mass and radius along the M-R curve. By performing calculations at two frequently referenced neutron stars, we further examine how the changes in mass and radius correlate with the nuclear matter properties at saturation density. Our results suggest that the 716Hz rotational constraint may require a more conservative interpretation when accounting for realistic stellar deformation effects. Conclusions: To place stringent constraints on the nuclear EoS based on observational data, it is sometimes essential to account for the effects of rotation in neutron star models. In particular, the influence of rotation becomes increasingly significant at higher spin frequencies and cannot be neglected in rapidly rotating systems with $>$400Hz.
- [78] arXiv:2505.20996 (cross-list from gr-qc) [pdf, html, other]
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Title: Parameter inference of microlensed gravitational waves using neural spline flowsComments: 11 pages, 6 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
When gravitational waves (GWs) propagate near massive objects, they undergo gravitational lensing that imprints lens model dependent modulations on the waveform. This effect provides a powerful tool for cosmological and astrophysical studies. However, conventional Bayesian parameter inference methods for GWs are computationally expensive, especially for lensed events with additional lens parameters, necessitating more efficient approaches. In this work, we explore the use of neural spline flows (NSFs) for posterior inference of microlensed GWs, and successfully apply NSFs to the inference of 13-dimensional lens parameters. Our results demonstrate that compared with traditional methods like Bilby dynesty that rely on Bayesian inference, the NSF network we built not only achieves inference accuracy comparable to traditional methods for the main parameters, but also can reduce the inference time from approximately 3 days to 0.8 s on average. Additionally, the network exhibits strong generalization for the spin parameters of GW sources. It is anticipated to become a powerful tool for future low-latency searches for lensed GW signals.
- [79] arXiv:2505.21188 (cross-list from quant-ph) [pdf, html, other]
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Title: Optimized quantum sensor networks for ultralight dark matter detectionComments: 7 pages, 6 figuresSubjects: Quantum Physics (quant-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
Dark matter (DM) remains one of the most compelling unresolved problems in fundamental physics, motivating the search for new detection approaches. We propose a network-based quantum sensor architecture to enhance sensitivity to ultralight DM fields. Each node in the network is a superconducting qubit, interconnected via controlled-Z gates in symmetric topologies such as line, ring, star, and fully connected graphs. We investigate four- and nine-qubit systems, optimizing both state preparation and measurement using a variational quantum metrology framework. This approach minimizes the quantum and classical Cramer-Rao bounds to identify optimal configurations. Bayesian inference is employed to extract the DM-induced phase shift from measurement outcomes. Our results show that optimized network configurations significantly outperform conventional GHZ-based protocols while maintaining shallow circuit depths compatible with noisy intermediate-scale quantum hardware. Sensitivity remains robust under local dephasing noise. These findings highlight the importance of network structure in quantum sensing and point toward scalable strategies for quantum-enhanced DM detection.
- [80] arXiv:2505.21359 (cross-list from gr-qc) [pdf, html, other]
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Title: Teleparallel dark energy in a nonflat universeComments: 12 pages, 4 figures. Published in PRDJournal-ref: Phys. Rev. D 111, 104076 (2025)Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In this paper, we investigate the cosmological dynamics of teleparallel dark energy in the presence of nonzero spatial geometry. Extending previous analyses of nonminimal scalar-tensor theories in the torsion-based framework, we consider different scalar field potentials and examine the resulting background evolution and linear perturbations. Adopting a dynamical systems approach, we reformulate the field equations and constrain the model parameters via a Markov chain Monte Carlo analysis combining updated datasets from Pantheon+SH0ES supernovae, cosmic chronometers, and growth rate measurements. Our results suggest a mild preference for an open geometry, although all models remain consistent with a flat universe at the $1\sigma$ level. Notably, Bayesian information criteria indicate that the nonflat teleparallel scenario with a vanishing potential is strongly favored over the standard $\Lambda$CDM model. Furthermore, all teleparallel scenarios are compatible with local determinations of the Hubble constant and exhibit better agreement with low-redshift structure formation data compared to $\Lambda$CDM. These findings highlight the potential of nonflat teleparallel gravity to address current observational tensions and motivate its further investigation as a viable alternative to standard cosmology.
- [81] arXiv:2505.21489 (cross-list from hep-th) [pdf, html, other]
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Title: 5-Dimensional Gravitational Raman Scattering: Scalar Wave Perturbations in Schwarzschild-Tangherlini SpacetimeComments: 15 pagesSubjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
In this Letter, we study scalar wave perturbations of arbitrary frequency to the 5D Schwarzschild-Tangherlini black hole (STBH) within general relativity. For the first time, we derive a closed formula for the 5D partial wave gravitational Raman scattering amplitude applicable to a broad class of boundary conditions, expressed in terms of the Nekrasov-Shatashvili (NS) function for the reduced confluent Heun problem. Furthermore, up to $O(G^2)$ we compute the dynamical $\ell=0$, and the static $\ell=1$, scalar tidal Love numbers of the STBH by matching an effective field theory description for a scalar wave scattering off the black hole, to our novel ultraviolet-NS solutions. The matched Love numbers do not vanish and present renormalization group running behavior.
Cross submissions (showing 15 of 15 entries)
- [82] arXiv:2308.13614 (replaced) [pdf, html, other]
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Title: The role of interior dynamics and differentiation on the surface and atmosphere of lava planetsCharles-Édouard Boukaré, Daphné Lemasquerier, Nicolas Cowan, Henri Samuel, James Badro, Lisa Dang, Aurélien Falco, Sébastien CharnozComments: 12 pages, 4 figures. Supplementary informations are includedSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Fluid Dynamics (physics.flu-dyn); Geophysics (physics.geo-ph)
Lava planets are rocky exoplanets that orbit so close to their host star that their day-side is hot enough to melt silicate rock. Their short orbital periods ensure that lava planets are tidally locked into synchronous rotation, with permanent day and night hemispheres. Such asymmetric magma oceans have no analogs in the Solar System and will exhibit novel fluid dynamics.
Here we report numerical simulations of lava planet interiors showing that solid-liquid fractionation in the planetary interior has a major impact on the compositional structure and evolution of the planet. We explored two styles of dynamics that depend primarily on the interior thermal state : 1) a hot fully molten interior, and 2) a mostly solid interior with a shallow day-side magma ocean.
In the hot interior scenario, the atmosphere reflects the planet's bulk silicate composition and the night-side crust is gravitationally unstable and constantly replenished. In the cool interior scenario, the distilled atmosphere will lack Na, K and FeO, and the night-side mantle is entirely solid, with a cold surface. These two end-member cases can be distinguished with observations from the James Webb Space Telescope, offering an avenue to probe the diversity of terrestrial exoplanet evolutions. - [83] arXiv:2402.18306 (replaced) [pdf, html, other]
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Title: Calibration requirement for Epoch of Reionization 21-cm signal observation -- III. Bias and variance in uGMRT ELAIS-N1 field power spectrumSaikat Gayen, Rashmi Sagar, Sarvesh Mangla, Prasun Dutta, Nirupam Roy, Arnab Chakraborty, Jais Kumar, Abhirup Datta, Samir ChoudhuriComments: 19 pages, 6 figuresJournal-ref: Journal of Cosmology and Astroparticle Physics, Volume 2024, May 2024Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Power spectrum of \HI 21-cm radiation is one of the promising probes to study large scale structure of the universe and understand galaxy formation and evolution. The presence of foregrounds, that are orders of magnitude larger in the same frequency range of the redshifted 21-cm signal has been one of the largest observational challenges. The foreground contamination also hinders the calibration procedures and introduces residual calibration errors in the interferometric data. It has been shown that the calibration errors can introduce bias in the 21-cm power spectrum estimates and introduce additional systematics. In this work, we assess the efficacy of 21-cm power spectrum estimation for the uGMRT Band-3 observations of the ELAIS-N1 field. We first evaluate the statistics of the residual gain errors and perform additional flagging based on these statistics. We then use an analytical method to estimate the bias and variance in the power spectrum. We found that (a) the additional flagging based on calibration accuracy help reduce the bias and systematics in the power spectrum, (b) the majority of the systematics at the lower angular scales, $\ell < 6000$, are due to the residual gain errors, (c) for the uGMRT baseline configuration and system parameters, the variance is always higher than the bias in the power spectrum estimates. Based on our analysis we observe that for an angular multipole of $\ell \sim3000$, $2000$ hours of `on source time' is required with the uGMRT to detect redshifted 21-cm signal at $3-\sigma$ significance from a redshift of $2.55$. In this work we only consider the power spectrum measurement in the plane of the sky, an assessment of residual gain statistics and its effect on multifrequency angular power spectrum estimation for the uGMRT and the SKA like telescopes will be presented in a companion paper.
- [84] arXiv:2408.15949 (replaced) [pdf, html, other]
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Title: Probing Lorentz invariance with a high-energy neutrino flareComments: 19 pages, 7 figures, plus an appendix, version accepted for publication in Physical Review DSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
Time-of-flight measurements of high-energy astrophysical neutrinos can be used to probe Lorentz invariance, a pillar of modern physics. If Lorentz-invariance violation (LIV) occurs, it could cause neutrinos to slow down, with the delay scaling linearly or quadratically with their energy. We introduce non-parametric statistical methods designed to detect LIV-induced distortions in the temporal structure of a high-energy neutrino flare as it travels to Earth from a distant astrophysical source, independently of the intrinsic timing properties of the source. Our approach, illustrated using the 2014/2015 TeV-PeV neutrino flare from the blazar TXS 0506+056 detected by IceCube, finds that the LIV energy scale must exceed 10^{14} GeV (linear) or 10^9 GeV (quadratic). Our methods provide a robust means to investigate LIV by focusing solely on a neutrino flare, without relying on electromagnetic counterparts, and account for realistic energy and directional uncertainties. For completeness, we compare our limits inferred from TXS 0506+056 to the sensitivity inferred from multi-messenger detection of tentative coincidences between neutrinos and electromagnetic emission from active galactic nuclei and tidal disruption events.
- [85] arXiv:2409.05947 (replaced) [pdf, html, other]
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Title: The Role of High-mass Stellar Binaries in the Formation of High-mass Black Holes in Dense Star ClustersComments: 19 pages, 15 figures, and 2 tables; in press for publication in the Astrophysical JournalSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Recent detections of gravitational waves from mergers of binary black holes (BBHs) with pre-merger source-frame individual masses in the so-called upper mass-gap, expected due to (pulsational) pair instability supernova ((P)PISN), have created immense interest in the astrophysical production of high-mass black holes (BHs). Previous studies show that high-mass BHs may be produced via repeated BBH mergers inside dense star clusters. Alternatively, inside dense star clusters, stars with unusually low core-to-envelope mass ratios can form via mergers of high-mass stars, which then can avoid (P)PISN, but produce high-mass BHs via mass fallback. We simulate detailed star-by-star multi-physics models of dense star clusters using the Monte Carlo cluster evolution code, CMC, to investigate the role of primordial binary fraction among high-mass stars (>=15 Msun) on the formation of high-mass BHs. We vary the high-mass stellar binary fraction (fb_15_prime) while keeping all other initial properties, including the population of high-mass stars, unchanged. We find that the number of high-mass BHs, as well as the mass of the most massive BH formed via stellar core-collapse are proportional to fb_15_prime. In contrast, there is no correlation between fb_15_prime and the number of high-mass BHs formed via BH-BH mergers. Since the total production of high-mass BHs is dominated by BH-BH mergers in old clusters, the overall number of high-mass BHs produced over the typical lifetime of globular clusters is insensitive to fb_15_prime. We study the differences in the demographics of BH-BH mergers and their implications for the LIGO-Virgo-Kagra detections as a function of fb_15_prime.
- [86] arXiv:2409.06527 (replaced) [pdf, html, other]
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Title: Hierarchical Bayesian inference on an analytical model of the LISA massive black hole binary populationComments: 19 pages, 11 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
Massive black hole binary (MBHB) mergers will be detectable in large numbers by the Lisa Interferometer Space Antenna (LISA), which will thus provide new insights on how they form via repeated dark matter (DM) halo and galaxy mergers. Here we present a simple analytical model to generate a population of MBHB mergers based on a theoretical prescription that connects them to DM halo mergers. The high flexibility of our approach allows us to explore the broad and uncertain range of MBH seeding and growth mechanisms, as well as the different effects behind the interplay between MBH and galactic astrophysics. Such a flexibility is fundamental for the successful implementation and optimisation of the hierarchical Bayesian parameter estimation approach that here we apply to the MBHB population of LISA for the first time. Our inferred population hyper-parameters are chosen as proxies to characterise the MBH--DM halo mass scaling relation, the occupation fraction of MBHs in DM halos and the delay between halo and MBHB mergers. We find that LISA will provide tight constraints at the lower-end of the MBH-halo scaling relation, well complementing EM observations which are biased towards large masses. Furthermore, our results suggest that LISA will constrain some features of the MBH occupation fraction at high redshift, as well as merger time delays of the order of a few hundreds of Myr, opening the possibility to constrain dynamical evolution time scales such as the dynamical friction. The analysis presented here constitutes a first attempt at developing a hierarchical Bayesian inference approach to the LISA MBHB population, opening the way for several further improvements and investigations.
- [87] arXiv:2411.17888 (replaced) [pdf, html, other]
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Title: A Novel Test for MOND: Gravitational Lensing by Disc GalaxiesComments: 18 pages, 12 figures, corrected error in phantom dark matter calculation and adjusted results accordingly, updated dark matter and MOND comparisonSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
Disc galaxies represent a promising laboratory for the study of gravitational physics, including alternatives to dark matter, owing to the possibility of coupling rotation curves' dynamical data with strong gravitational lensing observations. In particular, Euclid, DES and LSST are predicted to observe hundreds of thousands of gravitational lenses. Here, we investigate disc galaxy strong gravitational lensing in the MOND framework. We employ the concept of equivalent Newtonian systems within the quasi-linear MOND formulation to make use of the standard lensing formalism. We derive the phantom dark matter distribution predicted for realistic disc galaxy models and study the impact of morphological and mass parameters on the expected lensing. We find purely MONDian effects dominate the lensing and generate non-trivial correlations between the lens parameters and the lensing cross section. Moreover, we show that the standard realisation of MOND predicts a substantial increase in the number count of disc galaxy lenses compared to the dark matter-driven predictions, making it distinguishable from the latter in upcoming surveys. Finally, we argue that disc galaxy gravitational lensing, coupled to additional astronomical observations, can be used to constrain the interpolating function of MOND.
- [88] arXiv:2412.06372 (replaced) [pdf, html, other]
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Title: Numerical simulations of internal shocks in spherical geometry: hydrodynamics and prompt emissionComments: Accepted for publication in A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Among the models used to explain the prompt emission of gamma-ray bursts (GRBs), internal shocks is a leading one. Its most basic ingredient is a collision between two cold shells of different Lorentz factors in an ultra-relativistic outflow, which forms a pair of shock fronts that accelerate electrons in their wake. In this model, key features of GRB prompt emission such as the doubly-broken power-law spectral shape arise naturally from the optically-thin synchrotron emission at both shock fronts. We investigate the internal shocks model as a mechanism for prompt emission based on a full hydrodynamical analytic derivation in planar geometry, extending this approach to spherical geometry using hydrodynamic simulations. We used the moving mesh relativistic hydrodynamics code \texttt{GAMMA} to study the collision of two ultra-relativistic cold shells of equal kinetic energy (and power). Using the built-in shock detection, we calculate the corresponding synchrotron emission by the relativistic electrons accelerated into a power-law energy distribution behind the shock, in the fast cooling regime.}During the first dynamical time after the collision, the spherical effects cause the shock strength to decrease with radius. The observed peak frequency decreases faster than expected by other models in the rising part of the pulse, and the peak flux saturates even for moderately short pulses. This is likely caused by the very sharp edges of the shells in our model, while smoother edges will probably mitigate this effect. Our model traces the evolution of the peak frequency back to the source activity time scales.
- [89] arXiv:2412.18872 (replaced) [pdf, html, other]
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Title: Proton Flux Measurement from Neutron Monitor Data Using Neural NetworksComments: 15 pages, 8 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex); Space Physics (physics.space-ph)
Accurate measurements of cosmic ray proton flux are essential for studying the modulation processes of cosmic rays during the solar activity cycle. A proton flux measurement method, based on ground-based neutron monitor (NM) data and deep learning techniques, is presented. After the necessary pre-processing of ground-based NM data using a convolutional neural network (CNN) model, we simulate the relationship between NM observations and proton flux measured by the Alpha Magnetic Spectrometer (AMS). The daily proton flux data, ranging from 1 GV to 100 GV, are obtained for the period from 2011 to 2024, showing strong agreement with the observed values. In addition, daily proton flux measurements are provided for periods when AMS data were unavailable due to operational reasons. For the first time, hourly proton fluxes as a function of rigidity are calculated dedicated to the short-time solar activity studies.
- [90] arXiv:2501.15502 (replaced) [pdf, html, other]
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Title: The role of equation of state on the spin-up of millisecond pulsarsComments: 8 pages, 5 figures. SubmittedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Millisecond pulsars (MSPs) are recycled pulsars which have been spun-up due to mass accretion during the phase of mass exchange in binaries. Although the interactions with companion stars play important roles on the spin-up process, the global properties of pulsars determined by the equation of state (EoS), such as mass, radius and the moment of inertia, should also play a role. We investigate the spin-up of MSPs in neutron star (NS) and strangeon star (SS) models, both of which have passed the tests by the existence of high-mass pulsars and the tidal deformability of GW170817. Combining the spin-up condition and the transferred angular momentum, we can constrain the accreted mass and the magnetic field strength. The magnetic field strength will be important in impeding the spin-up of NSs, especially to the ones with low masses, but the impeding effect would not be important to SSs. The results indicate that it is easier for an SS to form a fully recycled low-mass MPS, whose spin-period is below 10 ms and mass is below about $1.5 M_\odot$, than that for an NS. Finding more low-mass and fully recycled MSPs, with accurate mass-measurement and better constraints on magnetic field strength, could help to put more strict constraints on the EoS of pulsars.
- [91] arXiv:2502.08528 (replaced) [pdf, html, other]
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Title: BCDDM: Branch-Corrected Denoising Diffusion Model for Black Hole Image GenerationComments: 20 pages, 10figuresJournal-ref: Astrophysical Journal Supplement Series, 2025Subjects: Astrophysics of Galaxies (astro-ph.GA); Computer Vision and Pattern Recognition (cs.CV)
The properties of black holes and accretion flows can be inferred by fitting Event Horizon Telescope (EHT) data to simulated images generated through general relativistic ray tracing (GRRT). However, due to the computationally intensive nature of GRRT, the efficiency of generating specific radiation flux images needs to be improved. This paper introduces the Branch Correction Denoising Diffusion Model (BCDDM), a deep learning framework that synthesizes black hole images directly from physical parameters. The model incorporates a branch correction mechanism and a weighted mixed loss function to enhance accuracy and stability. We have constructed a dataset of 2,157 GRRT-simulated images for training the BCDDM, which spans seven key physical parameters of the radiatively inefficient accretion flow (RIAF) model. Our experiments show a strong correlation between the generated images and their physical parameters. By enhancing the GRRT dataset with BCDDM-generated images and using ResNet50 for parameter regression, we achieve significant improvements in parameter prediction performance. BCDDM offers a novel approach to reducing the computational costs of black hole image generation, providing a faster and more efficient pathway for dataset augmentation, parameter estimation, and model fitting.
- [92] arXiv:2503.06895 (replaced) [pdf, html, other]
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Title: Analytical description for light propagation with the source inside the black hole photon sphereComments: 10 pages, 4 figures, minor revisions, references addedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
The photon sphere defines the unstable circular orbit of photons in a black hole spacetime. Photons emitted by a source located inside the photon sphere can be gravitationally lensed by the black hole and have time delays when reaching the observer. These delays may lead to light echoes produced in the light curve if an accretion event in the vicinity of the horizon can be observed. In this work, we present fully analytical formulas with high accuracy to describe the change of the azimuthal angle and the travel time of those photons. By employing the analytical approaches, we find that the time delay between photons emitted from the interior of the photon sphere has a typical time scale of $2(\pi - \phi_\mathrm{S}) u_\mathrm{m}$ with $\phi_\mathrm{S}$ and $u_\mathrm{m}$ being respectively the azimuthal angle of the source and the impact parameter evaluated at the photon sphere, which can provide some clues on the future search for gravitational lensing signatures in the accretion inflow event.
- [93] arXiv:2503.18937 (replaced) [pdf, other]
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Title: Multimodality in the Search for New Physics in Pulsar Timing Data and the Case of Kination-amplified Gravitational-wave Background from InflationComments: 5 figures, 1 table, matched to the published version in ApJJournal-ref: The Astrophysical Journal, 2025, Volume 985, Issue 1, id.117, 9 ppSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
We investigate the kination-amplified inflationary gravitational-wave background (GWB) interpretation of the signal recently reported by various pulsar timing array (PTA) experiments. Kination is a post-inflationary phase in the expansion history dominated by the kinetic energy of some scalar field, characterized by a stiff equation of state $w=1$. Within the inflationary GWB model, we identify two modes which can fit the current data sets (NANOGrav and EPTA) with equal likelihood: the kination-amplification (KA) mode and the ordinary, non-kination-amplification (no-KA) mode. The multimodality of the likelihood motivates a Bayesian analysis with nested sampling. We analyze the free spectra of current PTA data and mock free spectra constructed with higher signal-to-noise ratios, using nested sampling. The analysis of the mock spectrum designed to be consistent with the best fit to the NANOGrav 15 yr (NG15) data successfully reveals the expected bimodal posterior for the first time while excluding the reheating mode that appears in the fit to the current NG15 data, making a case for our correct treatment of potential multimodal posteriors arising from future PTA data sets. The resultant Bayes factor is $B\equiv Z_\mathrm{no-KA}/Z_\mathrm{KA}=2.9\pm1.9$, indicating comparable statistical significance between the two modes. Given the theoretical model-building challenges of producing highly blue-tilted primordial tensor spectra, the KA mode has the advantage of requiring a less blue primordial spectrum, compared with the no-KA mode. The synergy between future cosmic microwave background polarization, pulsar timing and laser interferometer measurements of gravitational waves will help resolve the ambiguity implied by the multimodal posterior in PTA-only searches.
- [94] arXiv:2503.19997 (replaced) [pdf, html, other]
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Title: A Cartesian catalog of 30 million Gaia sources based on second-order and Monte Carlo error propagationJournal-ref: Research in Astronomy and Astrophysics, 25, 055010 (2025)Subjects: Astrophysics of Galaxies (astro-ph.GA)
Accurate measurements of stellar positions and velocities are crucial for studying galactic and stellar dynamics. We aim to create a Cartesian catalog from Gaia DR3 to serve as a high-precision database for further research using stellar coordinates and velocities. To avoid the negative parallax values, we select 31,129,169 sources in Gaia DR3 with radial velocity, where the fractional parallax error is less than 20% ($0 < \sigma_\varpi/\varpi < 0.2$). To select the most accurate and efficient method of propagating mean and covariance, we use the Monte Carlo results with $10^7$ samples (MC7) as the benchmark, and compare the precision of linear, second-order, and Monte Carlo error propagation methods. By assessing the accuracy of propagated mean and covariance, we observe that second-order error propagation exhibits mean deviations of at most 0.5% compared to MC7, with variance deviations of up to 10%. Overall, this outperforms linear transformation. Though Monte Carlo method with $10^4$ samples (MC4) is an order of magnitude slower than second-order error propagation, its covariances propagation accuracy reaches 1% when $\sigma_\varpi/\varpi$ is below 15%. Consequently, we employ second-order error propagation to convert the mean astrometry and radial velocity into Cartesian coordinates and velocities in both equatorial and galactic systems for 30 million Gaia sources, and apply MC4 for covariance propagation. The Cartesian catalog and source code are provided for future applications in high-precision stellar and galactic dynamics.
- [95] arXiv:2503.23825 (replaced) [pdf, html, other]
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Title: Calibration requirements for Epoch of Reionization 21-cm signal observations -- IV. Bias and variance with time and frequency correlated residual gainsComments: 29 pages, 8 figures, 1 table, Accepted for publication in JCAP on 20 May 2025Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Observation of multifrequency angular power spectrum of the redshifted 21-cm brightness temperature fluctuation from the neutral hydrogen holds the key to understand the structure formation and its evolution during the reionization and post-reionization era. A major challenge in observing the neutral hydrogen arises from presence of strong foreground signals in the frequency range of interest. Mitigating the direct effect of foregrounds are being addressed through various techniques in literature. An additional second order effect arises, in presence of foreground, with limited accuracy in time and frequency dependent gain calibrations. This manifests as the residual gain and bandpass error in the observed data, introduces bias and increases uncertainty in the estimates of multifrequency angular power spectrum. In this work, we present an analytic method to estimate the bias and excess uncertainty in the estimates of multifrequency angular power spectrum in presence of residual gain and bandpass errors. We use this framework to estimate the effect of these errors for detection of redshifted 21-cm emission from a redshift of $\sim 8$ with the upcoming SKA1-Low. Due to the high baseline density at the required range of angular multipoles, the SKA1-Low is found to be a tuned instrument for the redshifted 21-cm signal detection. We find that, there are scenario with residual gain and bandpass errors where there can be significant bias in these estimates. Certain foreground mitigation strategies, is expected to reduce a part of the bias. The detailed study of different aspects of gain and bandpass errors and their relative effects are discussed. We find, with assumed models of gain and bandpass errors, signal detection is possible at this redshift with $128$ hours of observations. However, to achieve this one needs to have better calibration accuracy than present day interferometers.
- [96] arXiv:2503.24385 (replaced) [pdf, html, other]
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Title: Evolution of structure growth during dark energy domination: Insights from the cross-correlation of DESI galaxies with CMB lensing and galaxy magnificationNoah Sailer, Joseph DeRose, Simone Ferraro, Shi-Fan Chen, Rongpu Zhou, Martin White, Joshua Kim, Mathew MadhavacherilComments: published in PRDSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We use a Hybrid Effective Field Theory (HEFT) model to constrain the evolution of low-redshift $(z\lesssim0.4)$ matter fluctuations by cross-correlating DESI Bright Galaxy Survey (BGS) legacy imaging with the latest CMB lensing maps from Planck and ACT. Our tomographic BGS analysis finds that the evolution and amplitude of matter fluctuations align with CMB-conditioned $\Lambda$CDM predictions. When including DESI Baryon Acoustic Oscillation (BAO) measurements we obtain $\sigma_8 = 0.876^{+0.051}_{-0.067}$ from BGS alone. Jointly analyzing BGS and Luminous Red Galaxy (LRG) cross-correlations with the same CMB lensing maps yields $\sigma_8 = 0.791\pm0.021$. As a complementary approach we isolate the galaxy magnification signal from the cross-correlation of non-overlapping BGS and LRG photometric redshift bins, ruling out the null-magnification hypothesis at $11\sigma$. For the first time, we constrain structure growth from the (finite-difference calibrated) galaxy magnification signal and find $\sigma_8=0.720\pm0.047\,\,({\rm stat.})\pm0.050\,\,({\rm sys.})$ when adopting a linear bias model and including BAO data.
- [97] arXiv:2504.03422 (replaced) [pdf, html, other]
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Title: XXL-HSC: Host properties of X-ray detected AGNs in XXL clustersE. Drigga, E. Koulouridis, E. Pouliasis, Y. Toba, M. Akiyama, C. Vignali, A. Ruiz, I. Georgantopoulos, T. Nagao, S. Paltani, M. Plionis, M. Pierre, B. VijarnwannalukSubjects: Astrophysics of Galaxies (astro-ph.GA)
There is compelling evidence that AGNs are strongly influenced by their environment. Therefore, studying the AGN population of clusters is essential, as both large-scale structures and AGN play key roles in galaxy evolution, though the interactions between these elements are still not well understood. The primary objective of this study is to unravel the different factors that may significantly affect the triggering of AGN activity in cluster galaxies, including galaxy merging and interactions with other galaxies, and ram pressure from the hot intracluster medium. For our purposes, we used 82 X-ray detected AGN found within a $4r_{500}$ radius of 164 X-ray detected and spectroscopically confirmed galaxy clusters of the XXL survey, up to a redshift of $z\sim$1. This field is covered by deep optical observations of the Hyper Suprime-Cam, which allows for a reliable morphological classification of galaxies. Furthermore, using the X-ray hardness ratio, the optical spectra and the SEDs of the X-ray sources, we have studied the obscuration and other AGN properties and the SFR of the hosts as further indicators of interactions. We found a moderately significant higher fraction of X-ray AGN in galaxy clusters hosted by merging or disturbed galaxies, compared to non-active cluster galaxies or X-ray AGN in the field. This excess is primarily localised in the cluster outskirts. Also, we discovered a higher number of X-ray-hard AGN (hence, possibly obscured) in clusters than in the field particularly in the outskirts. These findings further support the idea that galaxy mergers and interactions may serve as mechanisms for the triggering and obscuration of AGN activity. The relatively high number of disturbed, merging, and possibly obscured AGN hosts in cluster outskirts suggests that galaxy merging and interactions are key drivers in triggering AGN activity in these outer regions of clusters.
- [98] arXiv:2504.10928 (replaced) [pdf, html, other]
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Title: Radiative-transfer models for dusty Type II supernovaeComments: accepted to A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Dust is expected to form on a year timescale in core-collapse supernova (SN) ejecta. Its existence is revealed through an infrared brightening, an optical dimming, or a blue-red emission-line profile asymmetry. To investigate how the dust location and amount impact observations, we computed ultraviolet-to-optical spectra of interacting and standard, noninteracting Type II SNe using state-of-the-art models -- for simplicity we adopted 0.1micron silicate grains. These models account for the full ejecta and treat both radioactive decay and shock power that arises from interaction of the ejecta with circumstellar material. In a Type IIn SN such as 1998S at one year, approximately 3e-4Msun of dust within the dense shell reproduces the broad, asymmetric Halpha profile. It causes an optical dimming of ~2mag (which obscures any emission from the inner, metal-rich ejecta) but, paradoxically, a more modest dimming of the ultraviolet, which originates from the outer parts of the dense shell. In Type II SNe with late-time interaction, such as SN2017eaw, dust in the low-mass, fast outer ejecta dense shell tends to be optically thin, impacting little the optical spectrum for dust masses of order 1e-4Msun. In such SNe II with interaction, dust in the inner metal-rich ejecta has negligible effect on observed spectra in the ultraviolet and optical. In noninteracting SNe II, dust within the metal-rich ejecta preferentially quenches the [OI]6300,6364 and [CaII]7291,7323 metal lines, biasing the emission in favor of the H-rich material which generates the Halpha and FeII emission below 5500A. Our model with 5e-4Msun of dust below 2000km/s matches closely the optical spectrum of SN1987A at 714d. Modeling historical SNe requires treating both the ejecta material and the dust, as well as multiple power sources, although interaction power will generally dominate.
- [99] arXiv:2504.15633 (replaced) [pdf, html, other]
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Title: An analytic redshift-independent formulation of baryonic effects on the matter power spectrumComments: 9 pages, 6 figures, accepted for publication in MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Baryonic effects created by feedback processes associated with galaxy formation are an important, poorly constrained systematic effect for models of large-scale structure as probed by weak gravitational lensing. Upcoming surveys require fast methods to predict and marginalize over the potential impact of baryons on the total matter power spectrum. Here we use the FLAMINGO cosmological hydrodynamical simulations to test a recent proposal to approximate the matter power spectrum as the sum of the linear matter power spectrum and a constant multiple, $A_{\rm mod}$, of the difference between the linear and non-linear gravity-only power spectra. We show that replacing this constant multiple with a one-parameter family of sigmoid functions of the wavenumber $k$ allows to us match the predictions of simulations with different feedback strengths for $z \leq 1, k < 3~h\cdot{\rm Mpc}^{-1}$, and the different cosmological models in the FLAMINGO suite. The baryonic response predicted by FLAMINGO models that use jet-like AGN feedback instead of the fiducial thermally-driven AGN feedback can also be reproduced, but at the cost of increasing the number of parameters in the sigmoid function from one to three. The assumption that $A_{\rm mod}$ depends only on $k$ breaks down for decaying dark matter models, highlighting the need for more advanced baryon response models when studying cosmological models that deviate strongly from $\Lambda$CDM.
- [100] arXiv:2504.20160 (replaced) [pdf, html, other]
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Title: The chemical enrichment histories across the Milky Way diskComments: In press in A&A, accepted 20 May 2025Subjects: Astrophysics of Galaxies (astro-ph.GA)
The variation of metal production over time and its dilution in the interstellar medium depend on the star formation and gas accretion rates. Measuring age-chemistry relations across the Milky Way disk provides key constraints on the gas accretion and star formation histories, and offers insight into the birth locations of stars. We present a study based on a sample of nearly 30000 dwarf stars from the APOGEE DR17 survey within 2 kpc of the Sun, for which we measure accurate ages. Various parameter combinations are tested to optimize stellar age determination from isochrones. The resulting age-chemistry relations for a selected subsample of 12000 stars are interpreted with the aid of a chemical evolution model. The data reveal a well-defined, tight thick disk sequence, characterized by high [alpha/Fe], subsolar metallicities, and ages older than 8 Gyr. The thin disk, with lower [alpha/Fe] and younger ages, exhibits a wide spread in metallicity at all ages, with apparent structures. Dividing the sample by guiding radius into inner, intermediate, and outer disks shows distinct chemical evolution patterns. The inner disk displays a monotonic, homogeneous chemical evolution with little dispersion, while the outer disk shows little metallicity increase over the past 8 Gyr. The solar neighborhood appears as a mixture, not only due to stellar migration but also because the chemical evolution of the ISM in this intermediate region results from the mixing of gas from the inner and outer disks. In particular, we demonstrate that the solar vicinity experienced a decrease in the mean ISM metallicity 7-9 Gyr ago. A plausible explanation involves a radial inflow of lower-metallicity gas from the outer disk at that time, which diluted the gas leftover by the thick disk formation, contributing to the observed metallicity gradient in the intermediate region.
- [101] arXiv:2505.01544 (replaced) [pdf, html, other]
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Title: Dark skies of the slightly eccentric WASP-18 b from its optical-to-infrared dayside emissionA. Deline, P. E. Cubillos, L. Carone, B.-O. Demory, M. Lendl, W. Benz, A. Brandeker, M. N. Günther, A. Heitzmann, S. C. C. Barros, L. Kreidberg, G. Bruno, D. Kitzmann, A. Bonfanti, M. Farnir, C. M. Persson, S. G. Sousa, T. G. Wilson, D. Ehrenreich, V. Singh, N. Iro, Y. Alibert, R. Alonso, T. Bárczy, D. Barrado Navascues, W. Baumjohann, M. Bergomi, N. Billot, L. Borsato, C. Broeg, M.-D. Busch, A. Collier Cameron, A. C. M. Correia, Sz. Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. D. S. Demangeon, A. Derekas, B. Edwards, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, K. Gazeas, M. Gillon, M. Güdel, J. Hasiba, Ch. Helling, K. G. Isaak, L. L. Kiss, J. Korth, K. W. F. Lam, J. Laskar, A. Lecavelier des Étangs, D. Magrin, P. F. L. Maxted, B. MerÃn, C. Mordasini, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I. Ribas, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, A. M. S. Smith, M. Stalport, S. Sulis, Gy. M. Szabó, S. Udry, V. Van Grootel, J. Venturini, E. Villaver, N. A. Walton, K. WesterdorffComments: 31 pages, 17 figures, 13 tables (including the appendix); accepted for publication in A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We performed a joint analysis of phase-curve observations of the ultra-hot Jupiter WASP-18 b from the visible to the mid-infrared, using data from CHEOPS, TESS and Spitzer. We aim to characterise the planetary atmosphere with a consistent view over the large wavelength range covered using GCMs and retrieval analyses, and including JWST data. We obtained new ephemerides with unprecedented precisions of 1 second and 1.4 millisecond on the time of inferior conjunction and orbital period, respectively. We computed a planetary radius of $R_p = 1.1926 \pm 0.0077 R_J$ with a precision of 0.65% (or 550 km). Based on a timing inconsistency with JWST, we discuss and confirm orbital eccentricity ($e = 0.00852 \pm 0.00091$). We also constrain the argument of periastron to $\omega = 261.9^{+1.3}_{-1.4}$ deg. We show that the large dayside emission implies the presence of magnetic drag and super-solar metallicity. We find a steep thermally inverted gradient in the planetary atmosphere, which is common for UHJs. We detected the presence of strong CO emission lines at 4.5 $\mu$m from an excess of dayside brightness in the Spitzer/IRAC/Ch2 passband. Using these models to constrain the reflected contribution in the CHEOPS passband, we derived an extremely low geometric albedo of $A_g^\text{CHEOPS} = 0.027 \pm 0.011$.
- [102] arXiv:2505.08051 (replaced) [pdf, html, other]
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Title: Impact of ACT DR6 and DESI DR2 for Early Dark Energy and the Hubble tensionComments: 7+5 pages, 5+2 figures, comments welcome. v2: added text regarding comparison with previous ACT results + refsSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The data release six of the Atacama Cosmology Telescope (ACT DR6) and the second data release from the Dark Energy Spectroscopic Instrument (DESI DR2) recently became available. In light of these data, we update constraints on the Early Dark Energy (EDE) resolution to the Hubble tension. While ACT DR6 does not favor EDE over the core cosmological model $\Lambda$CDM, it allows for a significantly larger maximum contribution of EDE, $f_{\rm EDE}$, in the pre-recombination era than the latest analysis of {\it Planck} NPIPE despite increased precision at small angular scales. Moreover, EDE rises the value of $H_0r_s$, improving consistency between CMB and DESI DR2 data. We find a residual tension with SH0ES of $\sim 2 \sigma$ for the combination of {\it Planck} at $\ell <1000$ + ACT DR6 + lensing + Pantheon-plus + DESI DR2, a significant decrease from $3.7 \sigma$ for analyses that use NPIPE and SDSS BAO data. A profile likelihood analysis reveals significant prior-volume effects in Bayesian analyses which do not include SH$0$ES, with confidence intervals of $f_{\rm EDE}=0.09\pm 0.03$ and $H_0= 71.0\pm1.1$ km/s/Mpc. When including DESI data, the EDE model with $H_0=73$ km/s/Mpc provides a better fit than the $\Lambda$CDM model with $H_0=68.4$ km/s/Mpc. The inclusion of SH$0$ES data rises the preference well above $5\sigma$, with $\Delta\chi^2=-35.4$. Our work demonstrates that after ACT DR6 and DESI DR2, EDE remains a potential resolution to the Hubble tension.
- [103] arXiv:2505.10214 (replaced) [pdf, html, other]
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Title: Using Machine Learning to Estimate Near-ultraviolet Magnitudes and Probe Quenching Mechanisms of $z$=0 Nuggets in the RESOLVE and ECO SurveysD. S. Carr, S. J. Kannappan, Z. L. Hutchens, M. S. Polimera, M. A. Norris, K. D. Eckert, A. J. MoffettComments: 20 pages, 7 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a $z=0$ census of nuggets -- compact galaxies that form via gas-rich violent disk instability -- within the luminosity- and volume-limited REsolved Spectroscopy Of a Local VolumE (RESOLVE) and Environmental COntext (ECO) surveys. We use random forest (RF) models to predict near-ultraviolet (NUV) magnitudes for ECO galaxies that lack high-quality NUV magnitudes, thereby doubling the number of ECO galaxies with reliable extinction-corrected star formation rates (SFRs) and red/green/blue classifications based on specific SFRs (sSFRs). The resulting RF-enhanced RESOLVE+ECO nugget sample allows us to analyze rare subpopulations -- green nuggets and nuggets with active galactic nuclei (AGN) -- likely associated with quenching. Green nuggets are more similar to red nuggets than to blue nuggets in halo mass ($M_{\text{halo}}$) distribution, with both red and green nuggets being found mainly at $M_{\text{halo}} \ge 10^{11.4} M_\odot$, where permanent halo quenching is predicted. At these masses, the AGN frequency for green nuggets is higher ($\text{48.2\%}^{+5.3\%}_{-5.3\%}$) than for either blue ($\text{39.2\%}^{+2.9\%}_{-2.8\%}$) or red ($\text{29.3\%}^{+3.0\%}_{-2.8\%}$) nuggets. Between $M_{halo} = 10^{11.4}-10^{12} M_\odot$, at the onset of permanent quenching, the AGN frequency for green nuggets is nearly double the frequency for blue or red nuggets, implying AGN are associated with this transition. At $M_{halo} < 10^{11.4} M_\odot$, where temporary cyclic quenching is expected, the AGN frequency for blue nuggets ($\text{7.5\%}^{+1.4\%}_{-1.2\%}$) is lower than for either green ($\text{31.3\%}^{+8.7\%}_{-7.5\%}$) or red ($\text{18.8\%}^{+11.5\%}_{-7.8\%}$) nuggets. At all masses, nuggets with AGN have reduced sSFRs and likely also atomic gas content compared to nuggets without AGN, but the quenching is more extreme below $M_{halo} = 10^{11.4} M_\odot$.
- [104] arXiv:2505.10235 (replaced) [pdf, html, other]
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Title: Implications of pulsar timing arrays for Gauss-Bonnet InflationComments: 19 pages + refs, 4 figures, references updated, submitted to journalSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
Correlated time-of-arrival measurements by pulsar timing arrays (PTAs) have provided a new means of constraining astrophysical or cosmological models that produce a gravitational wave (GW) background. For this work, we discuss the implications of PTA observations for Gauss-Bonnet (GB) inflationary models through the production and propagation of inflationary GWs. We show that our GB inflationary scenario is consistent with present PTA and cosmological data. A blue-tilted tensor power spectrum supported by PTAs can be naturally accommodated in GB inflation. Using observational constraints, we derive general conditions for the inflaton potential and the GB coupling function, suggesting that in GB inflation, the inflaton must climb up the potential before rolling downhill and reaching the end of inflation. We provide two concrete GB inflationary models to demonstrate the viability of this mechanism.
- [105] arXiv:2505.14662 (replaced) [pdf, html, other]
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Title: The Great Comets of 1843 and 1882 at Their Previous Return to Perihelion in the Twelfth Century: One Spectacular, the Other DullComments: 20 pages, 14 figures, 9 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
New insights into the history of C/1843 D1 and C/1882 R1, the two celebrated Kreutz sungrazers, are provided by assessing evidence on their appearance at the previous perihelion return, known as X/1106 C1 and the Chinese comet of 1138 (Ho's No. 403), respectively. The conditions differed vastly because of disparities in geocentric distance, solar elongation, and phase correction (forward scattering), all linked to the arrival times (early February vs early August). The conclusions include: the daytime sighting of the 1106 comet by Sigebert de Gembloux is consistent with expectation and so are the accounts of an exceptionally long tail observed later in twilight; the comet reached perihelion only hours before its daytime detection; the 1138 comet could have never been sighted in daylight or discovered much earlier than it actually was, in early September, one month after perihelion; at discovery, the tail is predicted to have reached elevations of 15-30 deg, while the head was only 10 deg above horizon, when observed from moderate northern latitudes; the notion that Kreutz sungrazers at perihelion between mid-May and mid-August could not be seen from the ground except possibly in daylight is misleading; the appearance of the 1138 comet's nucleus after its tidal fragmentation at perihelion is modeled on the assumption that it consisted of five major fragments (including C/1882 R1 and C/1965 S1); and unpredictable morphological changes with time in the 1882 sungrazer's split nucleus are discussed.
- [106] arXiv:2505.16562 (replaced) [pdf, html, other]
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Title: A Machine Learning Pipeline for Hunting Hidden Axion Signals in Pulsar Dispersion MeasurementsComments: 9 pages, 7 figures, Updated the paper structure and referencesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
In axion models, interactions between axions and electromagnetic waves induce frequency-dependent time delays determined by the axion mass and decay constant. These small delays are difficult to detect, limiting the effectiveness of traditional methods. We compute such delays under realistic radio telescope conditions and identify a prominent dispersive feature near half the axion mass, which appears non-divergent within the limits of observational resolution. Based on this, we develop a machine learning pipeline that achieves 95\% classification accuracy and demonstrates robust detection performance in low signal-to-noise regimes. When applied to PSR J1933-6211, no axion-induced delay is detected within current sensitivity limits. Future improvements in optical clock precision and telescope bandwidth, particularly with instruments such as the Qitai Radio Telescope, may enhance constraints on the axion decay constant by up to four orders of magnitude in the $10^{-6} \sim 10^{-4}$ eV mass range.
- [107] arXiv:2411.19674 (replaced) [pdf, html, other]
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Title: Finite parts of inflationary loopsComments: Infinitesimal modification on page 12. To appear on JHEPSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
We present a method for solving loop integrals in dimensional regularization that is particularly useful in the context of inflation. We apply this method to the calculation of the tensor power spectrum induced by scalar fluctuations in slow-roll inflation.
- [108] arXiv:2412.17738 (replaced) [pdf, html, other]
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Title: Symmetry-breaking inflation in non-minimal metric-affine gravityComments: 19 pages, 10 figures, matches published versionJournal-ref: JCAP 05, 072 (2025)Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We study symmetry-breaking inflation within the framework of metric-affine gravity. By introducing a non-minimal coupling, $\beta(\phi)\tilde{\cal R}$, between the Holst invariant and the inflaton, both small-field and large-field inflationary predictions can be brought into agreement with the latest observational constraints. Remarkably, even for sub-Planckian vacuum expectation values, appropriately chosen values of $\beta(\phi)$ enable viable inflation, a scenario previously considered unattainable.
- [109] arXiv:2412.19032 (replaced) [pdf, html, other]
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Title: Cosmological scenario based on the first and second laws of thermodynamics: Thermodynamic constraints on a generalized cosmological modelComments: Final version accepted for publication in EPJC. Several paragraphs and references are revised. [11 pages, 1 figure]Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The first and second laws of thermodynamics should lead to a consistent scenario for discussing the cosmological constant problem. In the present study, to establish such a thermodynamic scenario, cosmological equations in a flat Friedmann-Lemaître-Robertson-Walker universe were derived from the first law, using an arbitrary entropy $S_{H}$ on a cosmological horizon. Then, the cosmological equations were formulated based on a general formulation that includes two extra driving terms, $f_{\Lambda}(t)$ and $h_{\textrm{B}}(t)$, which are usually used for, e.g., time-varying $\Lambda (t)$ cosmology and bulk viscous cosmology, respectively. In addition, thermodynamic constraints on the two terms are examined using the second law of thermodynamics, extending a previous analysis [Phys. Rev. D 99, 043523 (2019) (arXiv:1810.11138)]. It is found that a deviation $S_{\Delta}$ of $S_{H}$ from the Bekenstein-Hawking entropy plays important roles in the two terms. The second law should constrain the upper limits of $f_{\Lambda}(t)$ and $h_{\textrm{B}}(t)$ in our late Universe. The orders of the two terms are likely consistent with the order of the cosmological constant $\Lambda_{\textrm{obs}}$ measured by observations. In particular, when the deviation $S_{\Delta}$ is close to zero, $h_{\textrm{B}}(t)$ and $f_{\Lambda}(t)$ should reduce to zero and a constant value (consistent with the order of $\Lambda_{\textrm{obs}}$), respectively, as if a consistent and viable scenario could be obtained from thermodynamics.
- [110] arXiv:2501.02052 (replaced) [pdf, html, other]
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Title: Search for continuous gravitational wave signals from luminous dark photon superradiance clouds with LVK O3 observationsLorenzo Mirasola, Cristina Mondino, Francesco Amicucci, Nils Siemonsen, Cristiano Palomba, Sabrina D'Antonio, Paola Leaci, Luca D'Onofrio, Pia Astone, Daniel Egana-Ugrinovic, Junwu Huang, Masha Baryakhtar, William E. EastComments: 26 pages, 8 figures; v2: published version, minor comments addedJournal-ref: Phys. Rev. D 111 (2025), 084032Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
Superradiance clouds of kinetically-mixed dark photons around spinning black holes can produce observable multi-messenger electromagnetic and gravitational wave signals. The cloud generates electric fields of up to a Teravolt-per-meter, which lead to a cascade production of charged particles, yielding a turbulent quasi-equilibrium plasma around the black hole, and resulting in electromagnetic fluxes ranging from supernova to pulsar-like luminosities. For stellar mass black holes, such systems resemble millisecond pulsars and are expected to emit pulsating radio waves and continuous gravitational waves (CWs) within the LIGO-Virgo-KAGRA (LVK) sensitivity band. We select 44 sources with approximately coincident frequencies or positive frequency drifts from existing pulsar catalogs as potential candidates of long-lasting superradiance clouds around old galactic black holes. For a subset of 34 sources that are well measured and have not been previously targeted, we perform the first search for CW emission in LVK data from the third observing run. We find no evidence of a CW signal and place 95% confidence level upper limits on the emitted strain amplitude. We interpret these results, together with limits from previous searches, in terms of the underlying dark photon theory by performing an analysis of the expected signals from superradiance clouds from galactic black holes. We find that, even for moderately spinning black holes, the absence of an observed CW signal disfavors a discrete set of dark photon masses between about $10^{-13}$ $\rm{eV}/c^2$ and $10^{-12}$ $\rm{eV}/c^2$ and kinetic mixing couplings in the range of $10^{-9}$-$10^{-7}$, subject to assumptions about the properties of the black hole population and the cloud's electromagnetic emission.
- [111] arXiv:2505.10926 (replaced) [pdf, html, other]
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Title: Graviton-photon conversion in stochastic magnetic fieldsComments: 29 pages, 6 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We study graviton-photon conversion in the presence of stochastic magnetic fields. Assuming Gaussian magnetic fields that may possess nontrivial helicity, and unpolarized gravitational waves (GWs) as the initial state, we obtain expressions for the intensity and linear/circular polarizations of GWs after propagation over a finite distance. We calculate both the expectation values and variances of these observables, and find their nontrivial dependence on the typical correlation length of the magnetic field, the propagation distance, and the photon plasma mass. Our analysis reveals that an observationally favorable frequency range with narrower variance can emerge for the intensity, while a peak structure appears in the expectation value of the circular polarization when the magnetic field has nonzero helicity. We also identify a consistency relation between the GW intensity and circular polarization.