Pope, Alexandra and Bussmann, R. Shane and Dey, Arjun and Meger, Nicole and Alexander, David M. and Brodwin, Mark and Chary, Ranga-Ram and Dickinson, Mark E. and Frayer, David T. and Greve, Thomas R. and Huynh, Minh and Lin, Lihwai and Morrison, Glenn and Scott, Douglas and Yan, Chi-Hung (2008) The nature of faint SPITZER-selected dust-obscured galaxies. Astrophysical Journal, 689 (1). pp. 127-133. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20090517-194717193
- Published Version
Restricted to Repository administrators only
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20090517-194717193
We use deep far-IR, submillimeter, radio, and X-ray imaging and mid-IR spectroscopy to explore the nature of a sample of Spitzer-selected dust-obscured galaxies (DOGs) in GOODS-N. A sample of 79 galaxies satisfy the criteria R − [ 24] > 14 (Vega) down to S_(24) > 100 μJy (median flux density S_(24) = 180 μJy). Twelve of these galaxies have IRS spectra available, which we use to measure redshifts and classify these objects as being dominated by star formation or active galactic nucleus (AGN) activity in the mid-IR. The IRS spectra and Spitzer photometric redshifts confirm that the DOGs lie in a tight redshift distribution around z ~ 2. Based on mid-IR colors, 80% of DOGs are likely dominated by star formation; the stacked X-ray emission from this subsample of DOGs is also consistent with star formation. Since only a small number of DOGs are individually detected at far-IR and submillimeter wavelengths, we use a stacking analysis to determine the average flux from these objects and plot a composite IR (8-1000 μm) spectral energy distribution (SED). The average luminosity of these star-forming DOGs is L_(IR) ~ 1 × 10^(12)L☉. We compare the average star-forming DOG to the average bright (S_(850) > 5 mJy) submillimeter galaxy (SMG); the S_(24) > 100 μJy DOGs are 3 times more numerous but 8 times less luminous in the IR. The far-IR SED shape of DOGs is similar to that of SMGs (average dust temperature of around 30 K), but DOGs have a higher mid-IR-to-far-IR flux ratio. The average star formation-dominated DOG has a star formation rate of 200 M☉ yr^(−1), which, given their space density, amounts to a contribution of 0.01 M☉yr^(−1) Mpc^(−3) (or 5%-10%) to the star formation rate density at z ~ 2.
|Additional Information:||© 2008 The American Astronomical Society. Received 2008 June 24, accepted for publication 2008 August 20. We thank the referee for constructive comments on this paper. We are grateful to Emanuele Daddi and Anna Sajina for insightful discussions. A. P. acknowledges support provided by NASA through the Spitzer Space Telescope Fellowship Program, through a contract issued by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. The research of A. P., A. D., M. B., and M. E. D. is supported in part by NOAO, which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. D. M. A. thanks the Royal Society for support. This work is based on observations made with the Spitzer Space Telescope,which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. We acknowledge L. Simard for leading the GOODS-N WIRCAM K-band proposal and L. Albert and the Terapix team for help on the WIRCAM data processing.|
|Subject Keywords:||galaxies: active; galaxies: evolution; galaxies: starburst; infrared: galaxies; submillimeter; X-rays: galaxies|
|Official Citation:||The Nature of Faint Spitzer-selected Dust-obscured Galaxies Alexandra Pope, R. Shane Bussmann, Arjun Dey, Nicole Meger, David M. Alexander, Mark Brodwin, Ranga-Ram Chary, Mark E. Dickinson, David T. Frayer, Thomas R. Greve, Minh Huynh, Lihwai Lin, Glenn Morrison, Douglas Scott, and Chi-Hung Yan 2008 ApJ 689 127-133 doi: 10.1086/592739|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Joy Painter|
|Deposited On:||18 Aug 2009 20:37|
|Last Modified:||26 Dec 2012 11:00|
Repository Staff Only: item control page