Dust correction factors over 0 < z < 3 in massive star-forming galaxies derived from a stacking analysis of Herschel data^⋆,⋆⋆

¹ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
e-mail: ivanoteogomez@gmail.com
² European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany

Received: 15 July 2014
Accepted: 4 September 2014

Abstract

We use a stacking analysis in Herschel/PACS to study the accuracy of several dust-correction factors that are typically employed to estimate the total star-formation rate (SFR) of high-redshift, massive, star-forming (SF) galaxies. We also analyze what stacking suggests about the relation between SFR and stellar mass and the redshift evolution of the specific SFR (sSFR = SFR/M_∗). We find that the dust properties of massive SF galaxies evolve with redshift, that is, galaxies at z ~ 2−3 are more attenuated than at z ~ 1 for a given UV continuum slope and stellar mass. As a consequence, a single IRX-β or dust-mass relation cannot be used to recover the total SFR of massive SF galaxies at 0 ≲ z ≲ 3. This might have implications for studies at higher redshifts, where a single IRX-β relation derived for local starbursts is usually assumed to be valid. However, we find evidence that the local relations might be valid at least up to z ~ 1, where bluer and less massive galaxies can be detected through stacking. The spectral energy distribution fitting procedure with stellar population templates gives overestimated values (about 0.3–0.5 dex in log SFR) of the dust-corrected SFR at all redshifts studied here. We find that the slope of the main-sequence of star formation is flatter than previously found in massive galaxies with log (M_∗/M_⊙) ≥ 10, and the redshift evolution of the sSFR reported in previous works in massive galaxies is well recovered.