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Infrared Properties of High Redshift and X-ray Selected AGN Samples

Wilkes, Belinda J. and Hooper, Eric J. and McLeod, Kim K. and Elvis, Martin S. and Hughes, David H. and Impey, Chris D. and Kuraszkiewicz, Joanna K. and Lonsdale, Carol S. and Malkan, Matt A. and McDowell, Jonathan C. (2001) Infrared Properties of High Redshift and X-ray Selected AGN Samples. In: ISO Surveys of a Dusty Universe. Lecture Notes in Physics. No.548. Springer , Berlin, pp. 177-184. ISBN 978-3-540-67479-5.

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The NASA/ISO Key Project on active galactic nuclei (AGN) seeks to better understand the broad-band spectral energy distributions (SEDs) of these sources from radio to X-rays, with particular emphasis on infrared properties. The ISO sample includes a wide variety of AGN types and spans a large redshift range. Two subsamples are considered herein: 8 high-redshift (1 < z < 4.7) quasars; and 22 hard X-ray selected sources. The X-ray selected AGN show a wide range of IR continuum shapes, extending to cooler colors than the optical/radio sample of [7]. Where a far-IR turnover is clearly observed, the slopes are < 2.5 in all but one case so that non-thermal emission remains a possibility. The highest redshift quasars show extremely strong, hot IR continua requiring ∼ 100M⊙ of 500–1000K dust with ∼ 100 times weaker optical emission. Possible explanations for these unusual properties include: reflection of the optical light from material above/below a torus; strong obscuration of the optical continuum; or an intrinsic deficit of optical emission. A cosmology of (H_0, Ω^m , Ω^k , Ω_Λ ) = (50 km s⁻¹ Mpc⁻¹, 1, 0, 0) is assumed.

Item Type:Book Section
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URLURL TypeDescription ReadCube access
Wilkes, Belinda J.0000-0003-1809-2364
Malkan, Matt A.0000-0001-6919-1237
Additional Information:© 2000 Springer-Verlag Berlin Heidelberg. First Online: 19 February 2001.
Group:Infrared Processing and Analysis Center (IPAC)
Subject Keywords:Active Galactic Nucleus; High Redshift; Star Formation Rate; Spectral Energy Distribution; Spectral Slope
Series Name:Lecture Notes in Physics
Issue or Number:548
Record Number:CaltechAUTHORS:20200107-160850970
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100550
Deposited By: Tony Diaz
Deposited On:08 Jan 2020 18:21
Last Modified:16 Nov 2021 17:54

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