Detecting Obscured AGN in the Distant Universe with Spitzer

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dc.creatorDonley, J. L.
dc.creatorRieke, G. H.
dc.creatorPerez-Gonzalez, P. G.
dc.creatorRigby, J. R.
dc.creatorAlonso-Herrero, A.
dc.date2006-12-12
dc.date.accessioned2026-07-07T06:34:40Z
dc.date.available2026-07-07T06:34:40Z
dc.descriptionWe present the results of a Spitzer search for obscured AGN in the Chandra Deep Field-North, using both radio-excess and mid-infrared power-law selection. AGN selected via the former technique tend to lie at z ~ 1, have SEDs dominated by the 1.6 micron stellar bump, and have Seyfert-like X-ray luminosities (when detected in the X-ray). In contrast, the IRAC (3.6-8.0 micron) power-law selected AGN lie at higher redshifts of z ~ 2, and comprise a significant fraction of the most X-ray luminous AGN in the CDF-N. While there is almost no overlap in the AGN samples selected via these two methods, their X-ray detection fractions are very similar. Only 40% and 55% of the radio-excess and power-law samples are detected in the 2 Ms X-ray catalog, respectively. The majority of the AGN selected via both methods are consistent with being obscured (N_H > 10^(22) cm^-2), but not Compton-thick (N_H > 10^(24) cm^-2), although Compton-thick candidates exist in both samples. We place an upper limit of <82% (or < 4:1) on the obscured fraction of the power-law sample, consistent with predictions from the cosmic X-ray background. The sources selected via the power-law criteria comprise a subset of AGN selected via other IRAC color-color cuts. While smaller in number than the color-selected samples in the deep fields, the power-law sample suffers from less contamination by star-forming galaxies.
dc.description6 pages, 2 figures, To appear in the proceedings of 'At the Edge of the Universe' (9-13 October 2006, Sintra, Portugal)
dc.identifierhttps://arxiv.org/abs/astro-ph/0612331
dc.identifierhttp://arxiv.org/abs/astro-ph/0612331
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/99597
dc.subjectAstrophysics
dc.titleDetecting Obscured AGN in the Distant Universe with Spitzer
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