GAMA/H-ATLAS: Common star-formation rate indicators and their dependence
  on galaxy physical parameters
  We compare common star-formation rate (SFR) indicators in the local Universe
in the GAMA equatorial fields (around 160 sq. deg.), using ultraviolet (UV)
photometry from GALEX, far-infrared (FIR) and sub-millimetre (sub-mm)
photometry from H-ATLAS, and Halpha spectroscopy from the GAMA survey. With a
high-quality sample of 745 galaxies (median redshift 0.08), we consider three
SFR tracers: UV luminosity corrected for dust attenuation using the UV spectral
slope beta (SFRUV,corr), Halpha line luminosity corrected for dust using the
Balmer decrement (BD) (SFRHalpha,corr), and the combination of UV and IR
emission (SFRUV+IR). We demonstrate that SFRUV,corr can be reconciled with the
other two tracers after applying attenuation corrections by calibrating IRX
(i.e. the IR to UV luminosity ratio) and attenuation in the Halpha (derived
from BD) against beta. However, beta on its own is very unlikely to be a
reliable attenuation indicator. We find that attenuation correction factors
depend on parameters such as stellar mass, z and dust temperature (Tdust), but
not on Halpha equivalent width (EW) or Sersic index. Due to the large scatter
in the IRX vs beta correlation, when compared to SFRUV+IR, the beta-corrected
SFRUV,corr exhibits systematic deviations as a function of IRX, BD and Tdust.
