The Hamburg/RASS Catalogue of optical identifications ^*

¹ Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg, Germany
² Max-Planck-Institut für extraterrestrische Physik, D-85740 Garching, Germany
³ ESTEC, Astrophysics Division, Postbus 299, NL-2200 AG Noordwijk, The Netherlands

Send offprint request to: N. Bade

Received: 13 February 1997
Accepted: 25 April 1997

Abstract

We present the Hamburg/RASS Catalogue of optical identifications (HRC). The catalogue contains optical information about objects inside the error circles of ROSAT All-Sky Survey (RASS) sources. The information was gathered from objective prism and direct plates taken by the Hamburg Quasar Survey (HQS). The plates enable an effective selection of several X-ray emitting classes of objects, as there are galaxies, AGN, QSOs, galaxy clusters and several types of galactic stars, in particular M dwarfs, hot white dwarfs and cataclysmic variables. In the current state (November 1996) the HRC contains information about 3847 X-ray positions and covers about 8480 deg² of the high galactic latitude |b| > 20°) northern sky. For 81.2% of the X-ray sources a plausible optical counterpart is given. The counterparts of the remaining sources are probably faint (B > 18.5) AGN and galaxy clusters. The HRC is available electronically together with finding charts taken from the digitized direct HQS plates.