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Ultradeep Spectroscopy with the Spitzer IRS

Teplitz, H. I. and Desai, V. and Armus, L. and Chary, R. and Colbert, J. W. and Frayer, D. T. and Pope, A. and Blain, A. and Spoon, H. and Charmandaris, V. and Scott, D. and Antonucci, S. (2008) Ultradeep Spectroscopy with the Spitzer IRS. In: The Second Annual Spitzer Science Center Conference: Infrared Diagnostics of Galaxy Evolution. ASP Conference Series. Vol.381. Astronomical Society of the Pacific , San Francisco, CA, pp. 357-362. ISBN 978-1-58381-325-6.

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Mid-IR spectroscopy has detected the signatures of star-formation (PAH emission) in high redshift (z > 1) ultra- and hyper-luminous infrared galaxies. However, the study of the dominant population of IR-luminous galaxies (10^(11) - 10^(12) Lsun at 1 < z < 3), requires observation of sources a at the 0.1 mJy level. We present the deepest spectra taken to date in the Long-Low module of the the Infrared Spectrometer (IRS) on the Spitzer Space Telescope. We targeted two faint (~0.15 mJy) sources in the Southern GOODS field at z = 1.09 and z = 2.69 as likely star-forming galaxies. Spectra of the lower redshift target were taken in 8-21 micron range (short-low first order and long-low second order), while the higher redshift target was observed from 21-37 microns (longlow first order). Observing times were 3 and 9 hours on-source for SL-1 and LL-2, respectively, and 12 hours for LL-1. We also present the spectra of two serendipitous sources. We detect strong PAH emission in four targets. We compare the spectra to those of local galaxies observed by the IRS. The z = 1.09 source appears to be a typical, star-formation dominated LIRG, while the z = 2.69 source is a composite source with strong star formation and a prominent AGN. The AGN component dominates the IRAC colors of this source, obscuring the 1.6 μm “bump.” Such sources would be excluded from IRAC surveys for starbursts which might then underestimate the star formation density.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Teplitz, H. I.0000-0002-7064-5424
Desai, V.0000-0002-1340-0543
Armus, L.0000-0003-3498-2973
Chary, R.0000-0001-7583-0621
Frayer, D. T.0000-0003-1924-1122
Pope, A.0000-0001-8592-2706
Blain, A.0000-0001-7489-5167
Spoon, H.0000-0002-8712-369X
Charmandaris, V.0000-0002-2688-1956
Scott, D.0000-0002-6878-9840
Additional Information:© 2008 Astronomical Society of the Pacific. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. 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
Series Name:ASP Conference Series
Record Number:CaltechAUTHORS:20100727-091616724
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:19193
Deposited By: Jason Perez
Deposited On:02 Aug 2010 04:58
Last Modified:16 Nov 2019 01:02

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