MULTIWAVELENGTH OBSERVATIONS OF THE FIELD HS-47.5 22 IN URSA-MAJOR - I - THE X-RAY CATALOG OF A MEDIUM DEEP ROSAT SURVEY/

We present the X-ray source catalogue obtained from a ROSAT survey in the HQS field HS 47.5/22. The survey consists of 48 overlapping PSPC p ointings which were first analysed individually, and then merged to in crease the sensitivity. Both modes bring forth sources missed in the o ther, showing that both are necessary to detect all X-ray sources in t he field. The final catalogue contains 574 X-ray sources. The identifi cations are mainly based on the HQS objective prism plate which allows object classification down to a magnitude m(b) less than or similar t o 18.(m)5, and a rough distinction between red and blue objects more t han a magnitude deeper. Follow-up observations were performed for a nu mber of objects, mainly faint quasar candidates.