SIMBAD references

An extremely deep X-ray survey (~1 Ms) of the Hubble Deep Field North (HDF-N) and its environs (~450 arcmin²) has been performed with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. This is one of the two deepest X-ray surveys ever performed; for point sources near the aim point, it reaches 0.5-2.0 and 2-8 keV flux limits of ~3x10^–17 and ~2x10^–16 ergs.cm^–2.s^–1, respectively. Here we provide source catalogs, along with details of the observations, data reduction, and technical analysis. Observing conditions, such as background, were excellent for almost all of the exposure. We have detected 370 distinct point sources: 360 in the 0.5-8.0 keV band, 325 in the 0.5-2.0 keV band, 265 in the 2-8 keV band, and 145 in the 4-8 keV band. Two new Chandra sources in the HDF-N itself are reported and discussed. Source positions are accurate to within 0".6-1".7 (at ~90% confidence), depending mainly on the off-axis angle. We also detect two highly significant extended X-ray sources and several other likely extended X-ray sources. We present basic number count results for sources located near the center of the field. Source densities of 7100⁺¹¹⁰⁰_–940 deg^–2 (at 4.2x10^–17 ergs.cm^–2.s^–1) and 4200⁺⁶⁷⁰_–580 deg^–2 (at 3.8x10^–16 ergs.cm^–2.s^–1) are observed in the soft and hard bands, respectively.