Mid-infrared selection of quasar-2s in Spitzer's First Look Survey

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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.
To appear in the proceedings of the workshop "Multiband approach to AGN" Bonn October 2004 in Memorie della Societa Astronomica Italiana

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Astrophysics

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http://salesiana.dossiersoluciones.com/handle/123456789/8566

Consulte el texto completo en el siguiente enlace:

https://arxiv.org/abs/astro-ph/0411416
 http://arxiv.org/abs/astro-ph/0411416

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arXiv