TheChandraDeep Protocluster Survey: point-source catalogues for a 400-ks observation of thez= 3.09 protocluster in SSA22

We present X-ray point-source catalogues for a deep 400-ks Chandra ACIS-I (Advanced CCD Imaging Spectrometer) exposure of the SSA22 field. The observations are centred on a z= 3.09 protocluster, which is populated by Lyman break galaxies (LBGs), Lyα emitters (LAEs) and extended Lyα-emitting blobs (LABs). The survey reaches ultimate (3 count) sensitivity limits of 5.7 × 10−17 and 3.0 × 10−16 erg cm−2 s−1 for the 0.5–2 and 2–8 keV bands, respectively (corresponding to L2-10 keV5.7 × 1042 erg s−1 and L10-30 keV2.0 × 1043 erg s−1 at z= 3.09, respectively, for an assumed photon index of Γ= 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, we detect 297 X-ray point sources and identify one obvious bright extended X-ray source over a 330 arcmin2 region. In addition to our X-ray catalogues, 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 (AGN) 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 1043–1045 erg 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.