Hc. Thomas et al., IDENTIFICATION OF SOFT HIGH GALACTIC LATITUDE RASS X-RAY SOURCES - I - A COMPLETE COUNT-RATE LIMITED SAMPLE, Astronomy and astrophysics (Berlin), 335(2), 1998, pp. 467-478
We present a summary of spectroscopic identifications for a complete s
ample of bright soft high galactic latitude X-ray sources drawn from t
he ROSAT All-Sky Survey which have PSPC count-rates CR > 0.5 cts s(-1)
and hardness ratios HR1 < 0. Of a total of 397 sources, 270 had catal
ogued counterparts although most of these were not previously known as
X-ray sources; of the remaining 127 sources neither X-ray nor optical
properties were previously known. Of the whole sample of very soft X-
ray sources 155 were also discovered by the Wide-Field-Camera on board
ROSAT. We present spectroscopic identifications of 108 sources and ot
her identifications for further 18 sources; 1 source remains unidentif
ied so far. In practically all cases a unique optical counterpart exis
ts facilitating identification. The largest source classes are AGN, ma
gnetic cataclysmic variables, and hot white dwarfs.