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arXiv · 0907.4369

The Chandra Deep Protocluster Survey: Point-Source Catalogs for a 400 ks Observation of the z = 3.09 Protocluster in SSA22

B. D. Lehmer·D. M. Alexander·S. C. Chapman·Ian Smail·F. E. Bauer·W. N. Brandt·J. E. Geach·Y. Matsuda·J. R. Mullaney·A. M. Swinbank
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Abstract

We present X-ray point-source catalogs for a deep 400 ks Chandra ACIS-I exposure of the SSA22 field. The observations are centred on a z = 3.09 protocluster, which is populated by Lyman break galaxies (LBGs), Lyalpha emitters (LAEs), and extended Lyalpha-emitting blobs (LABs). The survey reaches ultimate (3 count) sensitivity limits of 5.7 X 10^-17 and 3.0 X 10^-16 ergs cm^-2 s^-1 for the 0.5-2 keV and 2-8 keV bands, respectively. 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, we detect 297 X-ray point sources and identify one obvious bright extended X-ray source over a ~330 arcmin^2 region. In addition to our X-ray catalogs, we provide all available optical spectroscopic redshifts and near-infrared and mid-infrared photometry available for our sources. The basic X-ray and infrared properties of our Chandra sources indicate a variety of source types, although absorbed active galactic nuclei (AGNs) appear to dominate. In total, we 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 10^43-10^45 ergs s^-1 We 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.

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B. D. Lehmer, D. M. Alexander, S. C. Chapman, Ian Smail, F. E. Bauer, W. N. Brandt, J. E. Geach, Y. Matsuda, J. R. Mullaney, A. M. Swinbank. 2009-07-24. The Chandra Deep Protocluster Survey: Point-Source Catalogs for a 400 ks Observation of the z = 3.09 Protocluster in SSA22. https://doi.org/10.1111/j.1365-2966.2009.15449.x

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