TY - JOUR
T1 - The star formation histories of z ∼ 2 dust-obscured galaxies and submillimeter-selected galaxies
AU - Bussmann, R. S.
AU - Dey, Arjun
AU - Armus, L.
AU - Brown, M. J.I.
AU - Desai, V.
AU - Gonzalez, A. H.
AU - Jannuzi, B. T.
AU - Melbourne, J.
AU - Soifer, B. T.
PY - 2012/1/10
Y1 - 2012/1/10
N2 - The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z ∼ 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M *) of two populations of Spitzer-selected ULIRGs that have extremely red R - [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6μm associated with stellar emission ("bump DOGs"), while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ("power-law DOGs"). We measure M * by applying Charlot & Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M * values for SMGs, bump DOGs, and power-law DOGs are log(M */M) = 10.42 +0.42 - 0.36, 10.62+0.36 - 0.32, and 10.71+0.40 - 0.34, respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M *, a situation that arises more naturally in major mergers than in smooth accretion-powered systems.
AB - The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z ∼ 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M *) of two populations of Spitzer-selected ULIRGs that have extremely red R - [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6μm associated with stellar emission ("bump DOGs"), while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ("power-law DOGs"). We measure M * by applying Charlot & Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M * values for SMGs, bump DOGs, and power-law DOGs are log(M */M) = 10.42 +0.42 - 0.36, 10.62+0.36 - 0.32, and 10.71+0.40 - 0.34, respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M *, a situation that arises more naturally in major mergers than in smooth accretion-powered systems.
KW - galaxies: evolution
KW - galaxies: fundamental parameters
KW - galaxies: high-redshift
KW - galaxies: stellar content
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U2 - 10.1088/0004-637X/744/2/150
DO - 10.1088/0004-637X/744/2/150
M3 - Article
AN - SCOPUS:84555196217
VL - 744
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 150
ER -