Spitzer spectroscopy of 3C radio galaxies and quasars
- Creators
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Ogle, P. M.
- Whysong, D.
- Antonucci, R.
Abstract
We are conducting a large survey of Fanaroff-Riley class II radio galaxies and quasars at redshift z < 1 with the Spitzer Infrared Spectrograph. The goal is to determine which radio galaxies contain hidden active nuclei with luminosities comparable to quasars. We find that 40% of the radio galaxies have mid-IR power comparable to quasars of matched radio luminosity. These sources show thermal emission spectra from hot dust and silicate absorption from the dusty torus which blocks the optical nucleus from view. The mid-IR bright radio galaxies also show emission lines, such as [SIV], [NeV], and [NeVI], from gas that is highly ionized by the hidden nucleus. However, 60% of the radio galaxies are relatively weak mid-IR emitters, indicating that they do not contain a hidden, powerful accretion disk. Instead, their jets may be powered by a radiatively inefficient accretion flow or black hole spin.
Additional Information
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Received 5 October 2005; accepted 15 November 2005; published online 20 February 2006. 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 NASA contract 1407. Support for this work was provided by NASA through an award issued by JPL/Caltech. Note added in proof. Because of a systematic factor of 2 error in calculating luminosity distances, both the mid-IR and radio luminosities in Fig. 1 should be multiplied by a factor of 4. This does not otherwise affect any of the conclusions of this paper.Additional details
- Eprint ID
- 21839
- DOI
- 10.1002/asna.200510515
- Resolver ID
- CaltechAUTHORS:20110120-153025535
- NASA
- Created
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2011-02-03Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field