Volume 586, February 2016
|Number of page(s)||17|
|Section||Cosmology (including clusters of galaxies)|
|Published online||28 January 2016|
Dust attenuation in z ~ 1 galaxies from Herschel and 3D-HST Hα measurements
1 Dipartimento di Fisica e AstronomiaUniversità di Padova, vicolo dell’Osservatorio 2, 35122 Padova, Italy
2 Dipartimento di Fisica e Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy
3 INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
4 INAF–Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio, 5, 35122 Padova, Italy
5 Institute for Astronomy, Departement of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland
6 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, 85748 Garching, Germany
7 Max-Planck-Institut für Extraterrestrische Physik (MPE), Postfach 1312, 85741 Garching, Germany
8 Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, 91191 Gif sur Yvette, France
9 Astronomy Centre, Dept. of Physics & Astronomy, University of Sussex, Brighton BN1 9QH, UK
10 Kavli Institute for the Physics and Mathematics of the Universe, Todai Institute for Advanced Study, the University of Tokyo, 277-8583 Kashiwa, Japan
Received: 19 June 2015
Accepted: 28 November 2015
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 spectral energy distributions by fitting multiband 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 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, which is 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 ≳ 20M⊙/yr and M⋆ ≳ 5 × 1010M⊙, 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 extinction in the optical-UV continuum and suggest that the f-factor is a function of both M⋆ and SFR, in agreement with previous studies.
Key words: galaxies: star formation / galaxies: high-redshift / dust, extinction / infrared: ISM
© ESO, 2016
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