GOODS-HERSCHEL: star formation, dust attenuation and the FIR-radio
  correlation on the Main Sequence of star-forming galaxies up to z~4
  We use deep panchromatic datasets in the GOODS-N field, from GALEX to the
deepest Herschel far-infrared and VLA radio continuum imaging, to explore,
using mass-complete samples, the evolution of the star formation activity and
dust attenuation of star-forming galaxies to z~4. Our main results can be
summarized as follows: i) the slope of the SFR-M correlation is consistent with
being constant, and equal to ~0.8 at least up to z~1.5, while its normalization
keeps increasing with redshift; ii) for the first time here we are able to
explore the FIR-radio correlation for a mass-selected sample of star-forming
galaxies: the correlation does not evolve up to z~4; iii) we confirm that
galaxy stellar mass is a robust proxy for UV dust attenuation in star-forming
galaxies, with more massive galaxies being more dust attenuated, strikingly we
find that this attenuation relation evolves very weakly with redshift, the
amount of dust attenuation increasing by less than 0.3 magnitudes over the
redshift range [0.5-4] for a fixed stellar mass, as opposed to a tenfold
increase of star formation rate; iv) the correlation between dust attenuation
and the UV spectral slope evolves in redshift, with the median UV spectral
slope of star-forming galaxies becoming bluer with redshift. By z~3, typical UV
slopes are inconsistent, given the measured dust attenuation, with the
predictions of commonly used empirical laws. Finally, building on existing
results, we show that gas reddening is marginally larger (by a factor of around
1.3) than stellar reddening at all redshifts probed, and also that the amount
of dust attenuation at a fixed ISM metallicity increases with redshift. We
speculate that our results support evolving ISM conditions of typical
star-forming galaxies such that at z~1.5 Main Sequence galaxies have ISM
conditions getting closer to those of local starbursts.
