English

Finding Rare AGN: X-ray Number Counts of Chandra Sources in Stripe 82

Cosmology and Nongalactic Astrophysics 2015-06-11 v2

Abstract

We present the first results of a wide area X-ray survey within the Sloan Digital Sky Survey (SDSS) Stripe 82, a 300 deg2^2 region of the sky with a substantial investment in multi-wavelength coverage. We analyzed archival {\it Chandra} observations that cover 7.5 deg2^2 within Stripe 82 ("Stripe 82 ACX"), reaching 4.5σ\sigma flux limits of 7.9×1016\times10^{-16}, 3.4×1015\times10^{-15} and 1.8×1015\times10^{-15} erg s1^{-1} cm2^{-2} in the soft (0.5-2 keV), hard (2-7 keV) and full (0.5-7 keV) bands, to find 774, 239 and 1118 X-ray sources, respectively. Three hundred twenty-one sources are detected only in the full band and 9 sources are detected solely in the soft band. Utilizing data products from the {\it Chandra} Source Catalog, we construct independent LogNN-LogSS relationships, detailing the number density of X-ray sources as a function of flux, which show general agreement with previous {\it Chandra} surveys. We compare the luminosity distribution of Stripe 82 ACX with the smaller, deeper CDF-S + E-CDFS surveys and with {\it Chandra}-COSMOS, illustrating the benefit of wide-area surveys in locating high luminosity AGN. We also investigate the differences and similarities of X-ray and optical selection to uncover obscured AGN in the local Universe. Finally, we estimate the population of AGN we expect to find with increased coverage of 100 deg2^2 or 300 deg2^2, which will provide unprecedented insight into the high redshift, high luminosity regime of black hole growth currently under-represented in X-ray surveys.

Keywords

Cite

@article{arxiv.1210.0550,
  title  = {Finding Rare AGN: X-ray Number Counts of Chandra Sources in Stripe 82},
  author = {Stephanie M. LaMassa and C. Megan Urry and Eilat Glikman and Nico Cappelluti and Francesca Civano and Andrea Comastri and Ezequiel Treister and Arifin and Hans Boehringer and Carie Cardamone and Gayoung Chon and Miranda Kephart and Stephen S. Murray and Gordon Richards and Nic Ross and Joshua S. Rozner and Kevin Schawinski},
  journal= {arXiv preprint arXiv:1210.0550},
  year   = {2015}
}

Comments

Accepted for publication in MNRAS, 15 pages, 6 Figures, 2 Tables