Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-04-26
Astrophys.J.Suppl.173:267-292,2007
Astronomy and Astrophysics
Astrophysics
Accepted for publication in ApJ (Special GALEX Supplement issue - Dec 2007). v2: Typo in Eq. 2 corrected
Scientific paper
10.1086/519218
We measure star formation rates of ~50,000 optically-selected galaxies in the local universe (z~0.1), spanning a range from gas-rich dwarfs to massive ellipticals. We obtain dust-corrected SFRs by fitting the GALEX (UV) and SDSS (optical) photometry to a library of population synthesis models that include dust attenuation. For star-forming galaxies, our UV-based SFRs compare remarkably well with those derived from SDSS H alpha. Deviations from perfect agreement between these two methods are due to differences in the dust attenuation estimates. In contrast to H alpha, UV provides reliable SFRs for galaxies with weak or no H alpha emission, and where H alpha is contaminated with an emission from an AGN. We use full-SED SFRs to calibrate a simple prescription that uses GALEX UV magnitudes to produce good SFRs for normal star-forming galaxies. The specific SFR is considered as a function of stellar mass for (1) star-forming galaxies with no AGN, (2) those hosting an AGN, and for (3) galaxies without H alpha emission. We find that the three have distinct star formation histories, with AGN lying intermediate between the star-forming and the quiescent galaxies. Normal star forming galaxies (without an AGN) lie on a relatively narrow linear sequence. Remarkably, galaxies hosting a strong AGN appear to represent the massive continuation of this sequence. Weak AGN, while also massive, have lower SFR, sometimes extending to the realm of quiescent galaxies. We propose an evolutionary sequence for massive galaxies that smoothly connects normal star-forming galaxies to quiescent (red sequence) galaxies via strong and weak AGN. We confirm that some galaxies with no H alpha emission show signs of SF in the UV. We derive a UV-based cosmic SFR density at z=0.1 with smaller total error than previous measurements (abridged).
Bianchi Luciana
Brinchmann Jarle
Charlot Stephane
Donas Jose
Forster Karl
No associations
LandOfFree
UV Star Formation Rates in the Local Universe does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with UV Star Formation Rates in the Local Universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and UV Star Formation Rates in the Local Universe will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-676498