Mid-infrared selection of Quasar-2s in Spitzer's First Look Survey
Abstract
We present early results from the spectroscopic follow-up of a sample of candidate obscured AGN selected in the mid-infrared from the Spitzer First Look Survey. Our selection allows a direct comparison of the numbers of obscured and unobscured AGN at a given luminosity for the first time, and shows that the ratio of obscured to unobscured AGN at infrared luminosities corresponding to low luminosity quasars is ≈ 1:1 at z ~ 0.5. Most of our optically-faint candidate obscured AGN have the high-ionization, narrow-line spectra expected from type-2 AGN. A composite spectrum shows evidence for Balmer absorption lines, indicating recent star-formation activity in the host galaxies. There is tentative evidence for a decrease in the obscured AGN fraction with increasing AGN luminosity.
Additional Information
© 2005 SAIt. Società Astronomica Italiana. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology under NASA contract 1407. Support for this work was provided by NASA through JPL.Attached Files
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Additional details
- Eprint ID
- 75343
- Resolver ID
- CaltechAUTHORS:20170323-072953109
- NASA/JPL/Caltech
- 1407
- Created
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2017-03-23Created from EPrint's datestamp field
- Updated
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2019-11-07Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)