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arXiv · 1205.0811

Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS

Daniel Stern·Roberto J. Assef·Dominic J. Benford·Andrew Blain·Roc Cutri·Arjun Dey·Peter Eisenhardt·Roger L. Griffith·T. H. Jarrett·Sean Lake·Frank Masci·Sara Petty·S. A. Stanford·Chao-Wei Tsai·E. L. Wright·Lin Yan·Fiona Harrison·Kristin Madsen
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Abstract

The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1-W2 \geq 0.8 (i.e., [3.4]-[4.6] \geq 0.8, Vega), which identifies 61.9 \pm 5.4 AGN candidates per deg2 to a depth of W2 = 15.0. This implies a much larger census of luminous AGN than found by typical wide-area surveys, attributable to the fact that mid-infrared selection identifies both unobscured (type 1) and obscured (type 2) AGN. Optical and soft X-ray surveys alone are highly biased towards only unobscured AGN, while this simple WISE selection likely identifies even heavily obscured, Compton-thick AGN. Using deep, public data in the COSMOS field, we explore the properties of WISE-selected AGN candidates. At the mid-infrared depth considered, 160 uJy at 4.6 microns, this simple criterion identifies 78% of Spitzer mid-infrared AGN candidates according to the criteria of Stern et al. (2005) and the reliability is 95%. We explore the demographics, multiwavelength properties and redshift distribution of WISE-selected AGN candidates in the COSMOS field.

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Daniel Stern, Roberto J. Assef, Dominic J. Benford, Andrew Blain, Roc Cutri, Arjun Dey, Peter Eisenhardt, Roger L. Griffith, T. H. Jarrett, Sean Lake, Frank Masci, Sara Petty, S. A. Stanford, Chao-Wei Tsai, E. L. Wright, Lin Yan, Fiona Harrison, Kristin Madsen. 2012-05-03. Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS. https://doi.org/10.1088/0004-637x/753/1/30

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