AGN Populations in Large Volume X-ray Surveys: Photometric Redshifts and Population Types found in the Stripe 82X Survey

• Published in: arXiv.org
• Main Authors: Tonima, Tasnim Ananna, Salvato, Mara, LaMassa, Stephanie, Urry, Claudia Megan, Cappelluti, Nico, Cardamone, Carolin, Civano, Francesca, Duncan, Farrah, Gilfanov, Marat, Glikman, Eilat, Hamilton, Mark, Kirkpatrick, Allison, Lanzuisi, G, Marchesi, Stefano, Merloni, Andrea, Nandra, Kirpal, Natarajan, Priyamvada, Richards, Gordon, Timlin, John
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 11.10.2017
• Subjects: Active galactic nuclei; Luminosity; Outliers (statistics); Photometry; Physics - Astrophysics of Galaxies; Populations; Red shift; Sky surveys (astronomy); X ray sources
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1710.01296

Multi-wavelength surveys covering large sky volumes are necessary to obtain an accurate census of rare objects such as high luminosity and/or high redshift active galactic nuclei (AGN). Stripe 82X is a 31.3 deg\(^2\) X-ray survey with \(Chandra\) and \(XMM\)-Newton observations overlapping the legacy Sloan Digital Sky Survey (SDSS) Stripe 82 field, which has a rich investment of multi-wavelength coverage from the ultraviolet to the radio. The wide-area nature of this survey presents new challenges for photometric redshifts for AGN compared to previous work on narrow-deep fields because it probes different populations of objects that need to be identified and represented in the library of templates. Here we present an updated X-ray plus multi-wavelength matched catalog, including \(Spitzer\) counterparts, and estimated photometric redshifts for 5961 (96% of a total of 6181) X-ray sources, which have a normalized median absolute deviation, \(\sigma_{\rm nmad}\) = 0.06 and an outlier fraction, \(\eta\) = 13.7%. The populations found in this survey, and the template libraries used for photometric redshifts, provide important guiding principles for upcoming large-area surveys such as \(eROSITA\) and 3\(XMM\) (in X-ray) and the Large Synoptic Survey Telescope (LSST; optical).