Star formation rates and infrared radiation.
Abstract
Infrared colors and bolometric luminosities of galaxies are related to their ages and star formation rates. Models for old galaxies show that stellar age gradients could contribute to the V-K color gradients that have been observed in S0 galaxies. The interpretation of regions with star formation is complicated by the presence of dust. However, independently of reddening or reradiation by grains, unusually blue V-K colors or large bolometric luminosities per unit mass indicate a young age or a substantial burst of star formation. Under certain simplifying assumptions, notably that stars always form with the same mass spectrum, the following results hold within a factor of 2: If a region of a galaxy has a mass/bolometric luminosity ratio of less than 0.5 solar unit, then (1) its star formation rate in solar masses per billion years is roughly 0.2 times the bolometric luminosity in solar units and (2) the time scale for star formation to build the total mass is roughly 6(mass/bolometric luminosity ratio) billion years.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1978
- DOI:
- Bibcode:
- 1978ApJ...221..562S
- Keywords:
-
- Infrared Astronomy;
- Star Formation;
- Star Formation Rate;
- Stellar Spectra;
- Ubv Spectra;
- Bolometers;
- Galactic Evolution;
- Stellar Luminosity;
- Stellar Mass;
- Astrophysics;
- Galaxies:Infrared Radiation;
- Galaxies:Star Formation;
- Galaxies:Stellar Content