The Hamburg/RASS Catalogue of optical identifications

Abstract

\n We present the Hamburg/RASS Catalogue (HRC) of optical identifications of \nX-ray sources at high-galactic latitude. The HRC includes all X-ray sources \nfrom the ROSAT Bright Source Catalogue (RASS-BSC) \nwith galactic latitude $|b| \\ge 30\\degr$ and declination\n$\\delta \\ge 0\\degr$. \nIn this part of the sky covering ~10 000 deg2 the RASS-BSC \ncontains 5341 X-ray sources. For the optical identification we used \nblue Schmidt prism and direct plates taken for the northern\nhemisphere Hamburg Quasar Survey (HQS) which are now available in digitized form.\nThe limiting magnitudes are 18.5 and 20, respectively.\nFor 82% of the selected RASS-BSC an identification could be given. For the rest\neither no counterpart was visible in the error circle or a plausible\nidentification was not possible. With ~42% AGN represent the largest \ngroup of X-ray emitters, ~31% have a stellar counterpart, whereas\ngalaxies and cluster of galaxies comprise only ~4% and ~5%, \nrespectively. In ~3% of the RASS-BSC sources no object was visible on \nour blue direct plates within 40´´ around the X-ray source\nposition. The catalogue is used as a source for the selection of (nearly) \ncomplete samples of the various classes of X-ray emitters.\n\n \n

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Affiliated Institutions

• Universität Hamburg DE
• Max Planck Society DE
• Max Planck Institute for Extraterrestrial Physics DE
• European Space Research and Technology Centre NL
• Hamburger Fern-Hochschule DE

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