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Hubble Space Telescope Morphologies of z ~ 2 Dust Obscured Galaxies. I. Power-Law Sources
The Astrophysical Journal
  • R.S. Bussman, University of Arizona
  • Arjun Dey, National Optical Astronomy Observatory
  • J. Lotz, National Optical Astronomy Observatory
  • L. Armus, California Institute of Technology
  • K. Brand, Space Telescope Science Institute
  • M. J. I. Brown, Monash University
  • V. Desai, California Institute of Technology
  • P. Eisenhardt, California Institute of Technology
  • James L. Higdon, Georgia Southern University
  • Sarah J.U. Higdon, Physics
  • B. T. Jannuzi, National Optical Astronomy Observatory
  • E. Le Floc'H, University of Hawaii
  • J. Melbourne, California Institute of Technology
  • B. T. Soifer, Space Telescope Science Institute
  • D. Weedman, Cornell University
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We present high spatial resolution optical and near-infrared imaging obtained using the ACS, WFPC2 and NICMOS cameras aboard the Hubble Space Telescope of 31 24µm–bright z ≈ 2 Dust Obscured Galaxies (DOGs) identified in the Bo¨otes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral energy distributions dominated by a power-law component suggestive of an AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame UV or optical wavelengths. The observed V − H and I − H colors of the extended components are 0.2−3 magnitudes redder than normal star-forming galaxies. All but 1 have axial ratios > 0.3, making it unlikely that DOGs are composed of an edge-on star-forming disk. We model the spatially extended component of the surface brightness distributions of the DOGs with a S´ersic profile and find effective radii of 1 − 6 kpc. This sample of DOGs is smaller than most sub-millimeter galaxies (SMGs), but larger than quiescent high-redshift galaxies. Non-parametric measures (Gini and M20) of DOG morphologies suggest that these galaxies are more dynamically relaxed than local ULIRGs. We estimate lower limits to the stellar masses of DOGs based on the rest-frame optical photometry and find that these range from ∼ 109−11 M⊙. If major mergers are the progenitors of DOGs, then these observations suggest that DOGs may represent a post-merger evolutionary stage.


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Citation Information
R.S. Bussman, Arjun Dey, J. Lotz, L. Armus, et al.. "Hubble Space Telescope Morphologies of z ~ 2 Dust Obscured Galaxies. I. Power-Law Sources" The Astrophysical Journal Vol. 693 Iss. 1 (2009) p. 750 - 770
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