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Observations of Ultraluminous Infrared Galaxies with the IRS on Spitzer

Armus, L. (2006) Observations of Ultraluminous Infrared Galaxies with the IRS on Spitzer. In: The Spitzer Space Telescope: New Views of the Cosmos. ASP Conference Series. No.357. Astronomical Society of the Pacific , San Francisco, pp. 218-222. ISBN 978-1-58381-225-9.

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We present spectra taken with the Infrared Spectrograph on Spitzer covering the 5−38μm region of the ten Ultraluminous Infrared Galaxies (ULIRGs) found in the IRAS Bright Galaxy Sample. Among the BGS ULIRGs, we find a factor of 50 spread in the spectral slope from 5.5−60μm in the rest frame. There is evidence for water ice and hydrocarbon absorption (from 5.5−6.5μm) in 7/10 BGS ULIRGs, as well as absorption features of C2H2 and HCN in four and possibly six of the 10 BGS ULIRGs, indicating shielded molecular clouds and a warm, dense ISM. We have detected [NeV] emission at 14.3μm and 24.3μm in three out of the 10 BGS ULIRGs. The AGN fractions implied by either the [NeV]/[NeII] or [OIV]/[NeII] line flux ratios (or their upper limits) are significantly lower than implied by the MIR slope or strength of the 6.2μm PAH EQW feature.

Item Type:Book Section
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Armus, L.0000-0003-3498-2973
Additional Information:© 2006 Astronomical Society of the Pacific.
Group:Infrared Processing and Analysis Center (IPAC)
Series Name:ASP Conference Series
Issue or Number:357
Record Number:CaltechAUTHORS:20110121-142731926
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21853
Deposited By: Jason Perez
Deposited On:24 Jan 2011 21:38
Last Modified:24 Feb 2020 10:30

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