Herschel Far-IR counterparts of SDSS galaxies: Analysis of commonly used Star Formation Rate estimates

We study a hundred of galaxies from the spectroscopic Sloan Digital Sky
Survey with individual detections in the Far-Infrared Herschel PACS
bands (100 or 160 $\mu$m) and in the GALEX Far-UltraViolet band up to
z$\sim$0.4 in the COSMOS and Lockman Hole fields. The galaxies are
divided into 4 spectral and 4 morphological types. For the star forming
and unclassifiable galaxies we calculate dust extinctions from the UV
slope, the H$\alpha$/H$\beta$ ratio and the $L_{\rm IR}/L_{\rm UV}$
ratio. There is a tight correlation between the dust extinction and both
$L_{\rm IR}$ and metallicity. We calculate SFR$$ and compare it
with other SFR estimates (H$\alpha$, UV, SDSS) finding a very good
agreement between them with smaller dispersions than typical SFR
uncertainties. We study the effect of mass and metallicity, finding that
it is only significant at high masses for SFR${H\alpha}$. For the AGN
and composite galaxies we find a tight correlation between SFR and
{IR}$ ($\sigma\sim$0.29), while the dispersion in the SFR – L$
relation is larger ($\sigma\sim$0.57). The galaxies follow the
prescriptions of the Fundamental Plane in the M-Z-SFR space.