2015/07/31 by A. Puglisi, G. Rodighiero, A. Franceschini +12 · 1 citation
Physics and Astronomy · #astro-ph.GA #astro-ph.CO
paper · pdf · doi:10.1051/0004-6361/201526782
published as A&A 586, A83 (2016) · 19 pages, 17 figures. Accepted for publication in A&A
arxiv created 2015/12/02 · arxiv updated 2016/02/03
We combined the spectroscopic information from the 3D-HST survey with Herschel data to characterize the Hα dust attenuation properties of a sample of 79 main sequence star-forming galaxies at z ∼ 1 in the GOODS-S field. The sample was selected in the far-IR, at λ=100 and/or 160 μm, and only includes galaxies with a secure Hα detection (S/N>3). From the low resolution 3D-HST spectra we measured the redshifts and the Hα fluxes for the whole sample (a factor of 1/1.2 was applied to the observed fluxes to remove the [NII] contamination). The stellar masses (M⋆), infrared (LIR) and UV luminosities (LUV) were derived from the SEDs by fitting multi-band data from GALEX near-UV to SPIRE 500 μm. We estimated the continuum extinction Estar(B-V) from both the IRX=LIR/LUV ratio and the UV-slope, β, and found an excellent agreement between the two. The nebular extinction was estimated from comparison of the observed SFRHα and SFRUV. We obtained f=Estar(B-V)/Eneb(B-V)=0.93±0.06, i.e. higher than the canonical value of f=0.44 measured in the local Universe. Our derived dust correction produces good agreement between the Hα and IR+UV SFRs for galaxies with SFR\gtrsim 20 M\odot/yr and M⋆ \gtrsim 5 × 1010 M\odot, while objects with lower SFR and M⋆ seem to require a smaller f-factor (i.e. higher Hα extinction correction). Our results then imply that the nebular extinction for our sample is comparable to that in the optical-UV continuum and suggest that the f-factor is a function of both M⋆ and SFR, in agreement with previous studies.