HerMES: the far-infrared emission from dust-obscured galaxies

Calanog, J A, Wardlow, J, Fu, Hai, Cooray, A, Assef, R J, Bock, J, Casey, C M, Conley, A, Farrah, D, Ibar, E, Kartaltepe, J, Magdis, G, Marchetti, L, Oliver, S J, Pérez-Fournon, I, Riechers, D, Rigopoulou, D, Roseboom, I G, Schulz, B, Scott, Douglas, Symeonidis, M, Vaccari, M, Viero, M and Zemcov, M (2013) HerMES: the far-infrared emission from dust-obscured galaxies. The Astrophysical Journal, 775 (1). pp. 61-71. ISSN 0004-637X

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Abstract

Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg2 of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24μm and r+ observations using a color cut of r+ − [24] 7.5 (AB mag) and S24 100μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250μm (3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 1012 L) and (0.77 ± 0.08) × 1012 L), and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S24 100μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%–30% to the total star formation rate (SFR) density of the universe at z = 1.5–2.5, dominated by 250μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5–2.5 galaxies with S24 100μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy > QB0349 Theoretical astronomy and celestial mechanics
Depositing User: Catrina Hey
Date Deposited: 10 Sep 2014 14:14
Last Modified: 15 Mar 2017 03:16
URI: http://sro.sussex.ac.uk/id/eprint/49886

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Project NameSussex Project NumberFunderFunder Ref
Astronomy rolling grantG0278STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/I000976/1