Is There a Population of Obscured AGN?
Far-IR and Radio surveys suggest 50-80% of AGN in local universe are missed by optical/UV surveys because of dust obscuration
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- IRAS QSOs (Low et al. 1997)
- Red QSOs from radio surveys (Webster et al. 1995; Francis et al. 1999)
- Very red, luminous, high-z FIRST/2MASS AGN (Gregg et al. 2002)
- May account for at least part of XRB (e.g. Comastri et al. 1995)
But UV-excess/optical color-selected surveys appear to be 80-90% complete
- 2dF complete spectroscopic survey - 16.5<bjឃ.7 (Meyer et al. 2001)
- SDSS QSO survey (Ivezic et al. 2002)
Conduct a large-scale, uniform IR survey for reddened AGN