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Title: HUBBLE SPACE TELESCOPE MORPHOLOGIES OF z {approx} 2 DUST-OBSCURED GALAXIES. II. BUMP SOURCES

Abstract

We present Hubble Space Telescope imaging of 22 ultra-luminous infrared galaxies (ULIRGs) at z {approx} 2 with extremely red R - [24] colors (called dust-obscured galaxies, or DOGs) which have a local maximum in their spectral energy distribution (SED) at rest-frame 1.6 {mu}m associated with stellar emission. These sources, which we call 'bump DOGs', have star formation rates (SFRs) of 400-4000 M{sub sun} yr{sup -1} and have redshifts derived from mid-IR spectra which show strong polycyclic aromatic hydrocarbon emission-a sign of vigorous ongoing star formation. Using a uniform morphological analysis, we look for quantifiable differences between bump DOGs, power-law DOGs (Spitzer-selected ULIRGs with mid-IR SEDs dominated by a power law and spectral features that are more typical of obscured active galactic nuclei than starbursts), submillimeter-selected galaxies, and other less-reddened ULIRGs from the Spitzer Extragalactic First Look Survey. Bump DOGs are larger than power-law DOGs (median Petrosian radius of 8.4 {+-} 2.7 kpc versus 5.5 {+-} 2.3 kpc) and exhibit more diffuse and irregular morphologies (median M{sub 20} of -1.08 {+-} 0.05 versus -1.48 {+-} 0.05). These trends are qualitatively consistent with expectations from simulations of major mergers in which merging systems during the peak SFR period evolve from M{sub 20}more » = -1.0 to M{sub 20} = -1.7. Less-obscured ULIRGs (i.e., non-DOGs) tend to have more regular, centrally peaked, single-object morphologies rather than diffuse and irregular morphologies. This distinction in morphologies may imply that less-obscured ULIRGs sample the merger near the end of the peak SFR period. Alternatively, it may indicate that the intense star formation in these less-obscured ULIRGs is not the result of a recent major merger.« less

Authors:
 [1]; ; ;  [2]; ; ;  [3];  [4];  [5]; ;  [6];  [7];  [8];  [9]
  1. Steward Observatory, Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  2. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
  3. Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States)
  4. School of Physics, Monash University, Clayton, Victoria 3800 (Australia)
  5. Jet Propulsion Laboratory, California Institute of Technology, MC 169-327, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
  6. Georgia Southern University, P.O. Box 8031, Statesboro, GA (United States)
  7. Laboratoire AIM-Paris-Saclay, CEA-CNRS-Universite Paris Diderot, CEA Saclay, Gif-sur-Yvette, 91191 (France)
  8. Caltech Optical Observatories, California Institute of Technology, Pasadena, CA 91125 (United States)
  9. Astronomy Department, Cornell University, Ithaca, NY 14853 (United States)
Publication Date:
OSTI Identifier:
21576802
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 733; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/733/1/21; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DUSTS; GALACTIC EVOLUTION; GALAXIES; MORPHOLOGY; RED SHIFT; EVOLUTION

Citation Formats

Bussmann, R S, Dey, Arjun, Lotz, J, Jannuzi, B T, Armus, L, Desai, V, Soifer, B T, Brown, M J. I., Eisenhardt, P, Higdon, J, Higdon, S, Le Floc'h, E, Melbourne, J, and Weedman, D. HUBBLE SPACE TELESCOPE MORPHOLOGIES OF z {approx} 2 DUST-OBSCURED GALAXIES. II. BUMP SOURCES. United States: N. p., 2011. Web. doi:10.1088/0004-637X/733/1/21.
Bussmann, R S, Dey, Arjun, Lotz, J, Jannuzi, B T, Armus, L, Desai, V, Soifer, B T, Brown, M J. I., Eisenhardt, P, Higdon, J, Higdon, S, Le Floc'h, E, Melbourne, J, & Weedman, D. HUBBLE SPACE TELESCOPE MORPHOLOGIES OF z {approx} 2 DUST-OBSCURED GALAXIES. II. BUMP SOURCES. United States. https://doi.org/10.1088/0004-637X/733/1/21
Bussmann, R S, Dey, Arjun, Lotz, J, Jannuzi, B T, Armus, L, Desai, V, Soifer, B T, Brown, M J. I., Eisenhardt, P, Higdon, J, Higdon, S, Le Floc'h, E, Melbourne, J, and Weedman, D. 2011. "HUBBLE SPACE TELESCOPE MORPHOLOGIES OF z {approx} 2 DUST-OBSCURED GALAXIES. II. BUMP SOURCES". United States. https://doi.org/10.1088/0004-637X/733/1/21.
@article{osti_21576802,
title = {HUBBLE SPACE TELESCOPE MORPHOLOGIES OF z {approx} 2 DUST-OBSCURED GALAXIES. II. BUMP SOURCES},
author = {Bussmann, R S and Dey, Arjun and Lotz, J and Jannuzi, B T and Armus, L and Desai, V and Soifer, B T and Brown, M J. I. and Eisenhardt, P and Higdon, J and Higdon, S and Le Floc'h, E and Melbourne, J and Weedman, D},
abstractNote = {We present Hubble Space Telescope imaging of 22 ultra-luminous infrared galaxies (ULIRGs) at z {approx} 2 with extremely red R - [24] colors (called dust-obscured galaxies, or DOGs) which have a local maximum in their spectral energy distribution (SED) at rest-frame 1.6 {mu}m associated with stellar emission. These sources, which we call 'bump DOGs', have star formation rates (SFRs) of 400-4000 M{sub sun} yr{sup -1} and have redshifts derived from mid-IR spectra which show strong polycyclic aromatic hydrocarbon emission-a sign of vigorous ongoing star formation. Using a uniform morphological analysis, we look for quantifiable differences between bump DOGs, power-law DOGs (Spitzer-selected ULIRGs with mid-IR SEDs dominated by a power law and spectral features that are more typical of obscured active galactic nuclei than starbursts), submillimeter-selected galaxies, and other less-reddened ULIRGs from the Spitzer Extragalactic First Look Survey. Bump DOGs are larger than power-law DOGs (median Petrosian radius of 8.4 {+-} 2.7 kpc versus 5.5 {+-} 2.3 kpc) and exhibit more diffuse and irregular morphologies (median M{sub 20} of -1.08 {+-} 0.05 versus -1.48 {+-} 0.05). These trends are qualitatively consistent with expectations from simulations of major mergers in which merging systems during the peak SFR period evolve from M{sub 20} = -1.0 to M{sub 20} = -1.7. Less-obscured ULIRGs (i.e., non-DOGs) tend to have more regular, centrally peaked, single-object morphologies rather than diffuse and irregular morphologies. This distinction in morphologies may imply that less-obscured ULIRGs sample the merger near the end of the peak SFR period. Alternatively, it may indicate that the intense star formation in these less-obscured ULIRGs is not the result of a recent major merger.},
doi = {10.1088/0004-637X/733/1/21},
url = {https://www.osti.gov/biblio/21576802}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 733,
place = {United States},
year = {Fri May 20 00:00:00 EDT 2011},
month = {Fri May 20 00:00:00 EDT 2011}
}