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SSA22 Field Chandra X-Ray Point Source Catalog

Published by High Energy Astrophysics Science Archive Research Center | National Aeronautics and Space Administration | Metadata Last Checked: September 14, 2025 | Last Modified: 2025-09-10
This table contains the main X-ray point-source catalog for a deep ~400-ks Chandra ACIS-I (Advanced CCD Imaging Spectrometer) exposure of the SSA22 field. The observations were centred on a z = 3.09 protocluster, which is populated by Lyman break galaxies (LBGs), Lyman-alpha emitters (LAEs) and extended Lyman-alpha-emitting blobs (LABs). The survey reached ultimate (3 count) sensitivity limits of ~5.7 x 10<sup>-17</sup> and ~3.0 x 10<sup>-16</sup> erg cm<sup>-2</sup> s<sup>-1</sup> for the 0.5-2 and 2-8 keV bands, respectively (corresponding to L(2-10 keV) ~ 5.7 x 10<sup>42</sup> erg s<sup>-1</sup> and L(10-30 keV) ~ 2.0 x 10<sup>43</sup> erg s<sup>-1</sup> at z = 3.09, respectively, for an assumed photon index of Gamma = 1.4). These limits make SSA22 the fourth deepest extragalactic Chandra survey yet conducted, and the only one focused on a known high-redshift structure. In total, the authors detect 297 X-ray point sources and identify one obvious bright extended X-ray source (not included in the current table) over a ~330 arcmin<sup>2</sup> region. In addition to the X-ray data, the authors provide all available optical spectroscopic redshifts and near-infrared and mid-infrared photometry available for their sources. The basic X-ray and infrared properties of their Chandra sources indicate a variety of source types, although absorbed active galactic nuclei (AGN) appear to dominate. In total, they have identified 12 X-ray sources (either via optical spectroscopic redshifts or LAE selection) at z = 3.06 - 3.12 that are likely to be associated with the SSA22 protocluster. These sources have X-ray and multiwavelength properties that suggest they are powered by AGN with 0.5 - 8 keV luminosities in the range of ~ 10<sup>43</sup> - 10<sup>45</sup> erg s<sup>-1</sup>. The authors have analysed the AGN fraction of sources in the protocluster as a function of local LAE source density and find suggestive evidence for a correlation between AGN fraction and local LAE source density (at the ~96 per cent confidence level), implying that supermassive black hole growth at z ~3 is strongest in the highest density regions. This table was created by the HEASARC in February 2010 based on the electronic version of Table 2 from the reference paper which was obtained from the Monthly Notices web site. This is a service provided by NASA HEASARC .

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