Stellar Masses and SFRs for 1M Galaxies from SDSS and WISE

Understand

We combine SDSS and WISE photometry for the full SDSS spectroscopic galaxy sample, creating SEDs that cover lambda=0.4-22 micron for an unprecedented large and comprehensive sample of 858,365 present-epoch galaxies.

• Using MAGPHYS we then model simultaneously and consistently both the attenuated stellar SED and the dust emission at 12 micron and 22 micron, producing robust new calibrations for monochromatic mid-IR star formation rate proxies.
• These modeling results provide the first mid-IR-based view of the bi-modality in star formation activity among galaxies, exhibiting the sequence of star-forming galaxies (main sequence) with a slope of dlogSFR/dlogM*=0.80 and a scatter of 0.39 dex.
• We find that these new star-formation rates along the SF main sequence are systematically lower by a factor of 1.4 than those derived from optical spectroscopy.