Mapping the Clumpy Structures within Submillimeter Galaxies Using Laser-Guide Star Adaptive Optics Spectroscopy
Abstract
We present the first integral-field spectroscopic observations of high-redshift submillimeter-selected galaxies (SMGs) using Laser-Guide Star Adaptive Optics. We target Hα emission of three SMGs at redshifts z ~ 1.4-2.4 with the OH-Suppressing Infrared Imaging Spectrograph on Keck. The spatially resolved spectroscopy of these galaxies reveals unresolved broad-Hα line regions (FWHM >1000 km s^(–1)) likely associated with an active galactic nucleus (AGN) and regions of diffuse star formation traced by narrow-line Hα emission (FWHM ≾ 500 km s^(–1)) dominated by multiple Hα-bright stellar clumps, each contributing 1%-30% of the total clump-integrated Hα emission. We find that these SMGs host high star formation rate surface densities, similar to local extreme sources, such as circumnuclear starbursts and luminous infrared galaxies. However, in contrast to these local environments, SMGs appear to be undergoing such intense activity on significantly larger spatial scales as revealed by extended Hα emission over 4-16 kpc. Hα kinematics show no evidence of ordered global motion as would be found in a disk, but rather large velocity offsets (~few × 100 km s^(–1)) between the distinct stellar clumps. Together with the asymmetric distribution of the stellar clumps around the AGN in these objects, it is unlikely that we are unveiling a clumpy disk structure as has been suggested in other high-redshift populations of star-forming galaxies. The SMG clumps in this sample may correspond to remnants of originally independent gas-rich systems that are in the process of merging, hence triggering the ultraluminous SMG phase.
Additional Information
© 2013 American Astronomical Society. Received 2010 August 1; accepted 2013 February 4; published 2013 April 8. We thank the referee for useful comments and suggestions. We also thank David R. Law and Shelley Wright for helpful and insightful discussions on the treatment and analysis of OSIRIS observations. We are also grateful to the Keck support team for the fantastic on-site help in obtaining these observations, in particular to Al Conrad, Randy Campbell, Hien Tran, David LeMignant, Jim Lyke, and Christine Melcher. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. K.M.D. was supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-0802399. A.W.B. was supported by the NSF under award AST-0909159. I.R.S. acknowledges support from the Royal Society. This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.Attached Files
Published - 0004-637X_767_2_151.pdf
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Additional details
- Eprint ID
- 38621
- Resolver ID
- CaltechAUTHORS:20130521-152411737
- W. M. Keck Foundation
- AST-0802399
- NSF Astronomy and Astrophysics Postdoctoral Fellowship
- AST-0909159
- NSF
- Royal Society
- NASA/JPL/Caltech
- Created
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2013-05-21Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field