STELLAR MASSES AND STAR FORMATION RATES FOR 1 M GALAXIES FROM SDSS plus WISE

We combine Sloan Digitital Sky Survey (SDSS) and WISE photometry for the full SDSS spectroscopic galaxy sample, creating spectral energy distributions (SEDs) that cover lambda = 0.4-22 mu m for an unprecedentedly large and comprehensive sample of 858,365 present-epoch galaxies. Using MAGPHYS, we then simultaneously and consistently model both the attenuated stellar SED and the dust emission at 12 and 22 mu m, producing robust new calibrations for monochromatic mid-IR star formation rate (SFR) proxies. These modeling results provide the first mid-IR-based view of the bimodality in star formation activity among galaxies, exhibiting the sequence of starforming galaxies (main sequence) with a slope of d log SFR/d log M-* = 0.80 and a scatter of 0.39 dex. We find that these new SFRs along the SF main sequence are systematically lower by a factor of 1.4 than those derived from optical spectroscopy. We show that for most present-day galaxies, the 0.4-22 mu m SED fits can exquisitely predict the fluxes measured by Herschel at much longer wavelengths. Our analysis also illustrates that the majority of stars in the present-day universe are formed in luminous galaxies (similar to L*) in and around the green valley of the color-luminosity plane. We make publicly available the matched photometry catalog and SED modeling results.