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.
Dust attenuation in z ∼ 1 galaxies from Herschel and 3D-HST H α measurements / Puglisi, A.; Rodighiero, G.; Franceschini, A.; Talia, Margherita; Cimatti, Andrea; Baronchelli, I.; Daddi, E.; Renzini, A.; Schawinski, K.; Mancini, C.; Silverman, J.; Gruppioni, C.; Lutz, D.; Berta, S.; Oliver, S. J.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - STAMPA. - 586:(2016), pp. A83-A83. [10.1051/0004-6361/201526782]
Dust attenuation in z ∼ 1 galaxies from Herschel and 3D-HST H α measurements
TALIA, MARGHERITA;CIMATTI, ANDREA;
2016
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
