Journal article
Finding rare AGN: X-ray number counts of Chandra sources in Stripe 82
Monthly notices of the Royal Astronomical Society, v 432(2), pp 1351-1360
01 Jun 2013
Abstract
We present the first results of a wide-area X-ray survey within the Sloan Digital Sky Survey Stripe 82, a 300 deg(2) region of the sky with a substantial investment in multiwavelength coverage. We analysed archival Chandra observations that cover 6.2 deg(2) within Stripe 82 ('Stripe 82 ACX'), reaching 4.5 Sigma flux limits of 1.2 x 10(-15), 5.4 x 10(-15) and 2.9 x 10(-15) erg s(-1) cm(-2) in the soft (0.5-2 keV), hard (2-7 keV) and full (0.5-7 keV) bands, to find 480, 137 and 705 X-ray sources, respectively. 214 sources are detected only in the full band and 4 sources are detected solely in the soft band. Utilizing data products from the Chandra Source Catalog, we construct independent log N-log S relationships, detailing the number density of X-ray sources as a function of flux. The soft and full bands show general agreement with previous Chandra surveys; the hard band number counts agree among Stripe 82 ACX, XBootes and XDEEP2, but all three are somewhat systematically lower than the counts derived from Chandra Multiwavelength Project. We compare the luminosity distribution of Stripe 82 ACX with the smaller, deeper Chandra Deep Field-South, Extended Chandra Deep Field-South and Chandra-COSMOS surveys to illustrate the benefit of wide-area surveys in locating high-luminosity and/or high-redshift active galactic nuclei (AGN). Finally, we compare the identified AGN with predictions from population synthesis models, noting that prior to any spectroscopic follow-up campaign, we have already located roughly half the high-luminosity quasars at high redshift expected to lie within the survey area. However, our data also suggest that refinements to population synthesis models will be required.
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Details
- Title
- Finding rare AGN: X-ray number counts of Chandra sources in Stripe 82
- Creators
- Stephanie M. LaMassa - Yale UniversityC. Megan Urry - Yale UniversityEilat Glikman - Yale UniversityNico Cappelluti - Osservatorio astronomico di BolognaFrancesca Civano - 4Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USAAndrea Comastri - Osservatorio astronomico di BolognaEzequiel Treister - University of ConcepciónArifin - Natl Univ Singapore, Singapore 119077, SingaporeHans Boehringer - Max Planck Inst Extraterr Phys, D-85748 Garching, GermanyCarie Cardamone - 9Brown University, The Harriet W. Sheridan Center for Teaching and Learning, Box 1912, 96 Waterman Street, Providence, RI 02912, USAGayoung Chon - High Energy Astrophysics, MPI for Extraterrestrial Physics, Max Planck SocietyMiranda Kephart - Yale UniversityStephen S. Murray - Johns Hopkins UniversityGordon Richards - Drexel UniversityNicholas P. Ross - Lawrence Berkeley National LaboratoryJoshua S. Rozner - Yale UniversityKevin Schawinski - ETH Zurich
- Publication Details
- Monthly notices of the Royal Astronomical Society, v 432(2), pp 1351-1360
- Publisher
- Oxford Univ Press
- Number of pages
- 10
- Grant note
- PP00P2\_138979/1 / Swiss National Science Foundation; Swiss National Science Foundation (SNSF); European Commission
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000319832300039
- Scopus ID
- 2-s2.0-84878659247
- Other Identifier
- 991019168024204721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Astronomy & Astrophysics