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Mid-Infrared Spectroscopy of High-Redshift Submillimeter Galaxies: First Results

Menéndez-Delmestre, Karín and Blain, Andrew W. and Alexander, Dave M. and Smail, Ian and Armus, Lee and Chapman, Scott C. and Frayer, D. T. and Ivison, Rob J. and Teplitz, H. I. (2007) Mid-Infrared Spectroscopy of High-Redshift Submillimeter Galaxies: First Results. Astrophysical Journal Letters, 655 (2). L65-L68. ISSN 2041-8205. doi:10.1086/512038.

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We present mid-infrared spectra of five submillimeter galaxies at z = 0.65-2.38 taken with the Spitzer Space Telescope. Four of these sources, at z ≾ 1.5, have strong PAH features and their composite spectrum is well fitted by an M82-like spectrum with an additional power-law component consistent with that expected from AGN activity. Based on comparison with local templates of the 7.7 μm PAH equivalent width and the PAH-to-infrared luminosity ratio, we conclude that these galaxies host both star formation and AGN activity, with star formation dominating the bolometric luminosity. The source at z = 2.38 displays a Mrk 231-type broad emission feature at rest frame ~8 μm that does not conform to the typical 7.7 μm/8.6 μm PAH complex in starburst galaxies, suggesting a more substantial AGN contribution.

Item Type:Article
Related URLs:
URLURL TypeDescription
Blain, Andrew W.0000-0001-7489-5167
Alexander, Dave M.0000-0002-5896-6313
Smail, Ian0000-0003-3037-257X
Armus, Lee0000-0003-3498-2973
Frayer, D. T.0000-0003-1924-1122
Ivison, Rob J.0000-0001-5118-1313
Teplitz, H. I.0000-0002-7064-5424
Additional Information:© 2007 The American Astronomical Society. Received 2006 October 30; accepted 2006 December 21; published 2007 January 12. We thank our anonymous referee for valuable comments. We thank the Spitzer Science Center staff for their support, particularly Patrick Ogle for his help in the optimization of the spectral extraction. A. W. B. thanks the Research Corporation and the Alfred P. Sloan Foundation. D. M. A. and I. S. acknowledge support from the Royal Society. 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.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Research CorporationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:galaxies : active; galaxies : starburst; infrared : galaxies; techniques : spectroscopic
Issue or Number:2
Record Number:CaltechAUTHORS:20100222-144843965
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Official Citation:Mid-Infrared Spectroscopy of High-Redshift Submillimeter Galaxies: First Results Karín Menéndez-Delmestre, Andrew W. Blain, Dave M. Alexander, Ian Smail, Lee Armus, Scott C. Chapman, D. T. Frayer, Rob J. Ivison, and H. I. Teplitz 2007 ApJ 655 L65-L68 doi: 10.1086/512038
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17556
Deposited By: Tony Diaz
Deposited On:02 Mar 2010 17:35
Last Modified:08 Nov 2021 23:36

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