2013/10/31 by Sedona H. Price, Mariska Kriek, Gabriel Brammer +14 · 6 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Balmer series #Emission spectrum #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Photometry (optics) #Physics #Spectral line #Star formation #Stars #Stellar mass #Stellar population #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/788/1/86
Accepted for publication in the Astrophysical Journal (13 pages, 9 figures)
arxiv created 2014/04/21 · openalex publication_date 2014/05/23 · arxiv updated 2014/06/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The nature of dust in distant galaxies is not well understood, and until recently few direct dust measurements have been possible. We investigate dust in distant star-forming galaxies using near-infrared grism spectra of the 3D-HST survey combined with archival multi-wavelength photometry. These data allow us to make a direct comparison between dust around star-forming regions ( A V, H ii ) and the integrated dust content ( A V, star ). We select a sample of 163 galaxies between 1.36 ⩽ z ⩽ 1.5 with Hα signal-to-noise ratio ⩾5 and measure Balmer decrements from stacked spectra to calculate A V, H ii . First, we stack spectra in bins of A V, star , and find that A V, H ii = 1.86 A V, star , with a significance of σ = 1.7. Our result is consistent with the two-component dust model, in which galaxies contain both diffuse and stellar birth cloud dust. Next, we stack spectra in bins of specific star formation rate (log SSFR), star formation rate (log SFR), and stellar mass (log M * ). We find that on average A V, H ii increases with SFR and mass, but decreases with increasing SSFR. Interestingly, the data hint that the amount of extra attenuation decreases with increasing SSFR. This trend is expected from the two-component model, as the extra attenuation will increase once older stars outside the star-forming regions become more dominant in the galaxy spectrum. Finally, using Balmer decrements we derive dust-corrected Hα SFRs, and find that stellar population modeling produces incorrect SFRs if rapidly declining star formation histories are included in the explored parameter space.