Radio galaxies and type-2 quasars in the Spitzer Extragalactic First Look Survey
- Creators
- Lacy, M.
- Sajina, A.
- Gates, Elinor
- XFLS Team
Abstract
We use mid-infrared colour-colour plots made with data from the Spitzer First Look Survey to explore the emission mechanisms of faint radio sources in that field. Using mid-infrared colours alone, we are able to see the transition from a starburst-dominated radio source population at sub-mJy levels to the radiogalaxy/quasar population at mJy levels. Both FR I and some FR II galaxies show little or no mid-infrared excess, suggesting they either lack dusty tori, or a strong continuum source to heat them, or both. Objects with hot, dusty tori, most likely radio-intermediate and radio-quiet AGN, make up a significant fraction of the faint radio source population. We also discuss the use of mid-infrared colour-colour plots to select radio quiet obscured AGN. Early results from imaging the host galaxies of these type-2 quasars at high spatial resolution with adaptive optics indicates that they, like type-1 quasars and radio galaxies, are often found to be hosted by giant elliptical galaxies.
Additional Information
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Received 8 October 2005; accepted 15 November 2005; published online 20 February 2006. We would like to thank Gabriela Canalizo, Steve Rawlings and Alejo Martinez-Sansigre for helping with obtaining redshifts for some of the type-2 quasars.Additional details
- Eprint ID
- 23883
- Resolver ID
- CaltechAUTHORS:20110602-135032880
- Created
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2011-06-14Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field