THE X-PERSEI SYSTEM IN THE ROSAT ALL-SKY SURVEY

We report the analysis of soft X-ray data from the X-ray pulsar 4U 0352+30, taken by the ROSAT satellite. The mean luminosity, in the ROSAT bandpass (0.1-2.4 keV), is 6 x 10(33) d(kpc)2 erg s-1 and is consistent with that usually seen in the soft X-ray band. The energy spectrum can be described by a flat power-law attenuated by cold gas absorption with an average column density of 1 - 3 x 10(21) cm-2, close to estimates of the interstellar absorption towards the X Per system. The neutral hydrogen absorption is lower than that determined from hard X-ray observations. No soft excess as often seen in supergiant X-ray binaries is visible in the spectrum. The regular 96 min gaps in the data do not allow an independent estimate of the pulse period. The data were folded with a period, of 836.8 s, expected under the assumption of a constant spin down rate observed over the last years. Archival EXOSAT data suggest that during states of low neutral hydrogen absorption the soft flux has the same origin as the hard flux.