Forum Springer Astron. Astrophys.
Forum Whats New Search Orders

Astron. Astrophys. 318, 111-133 (1997)

Previous Section Next Section Title Page Table of Contents

10. Conclusions

We present the first results of a systematic identification programme of ROSAT all-sky survey sources in the galactic plane. The test region analyzed in this paper was chosen to be typical of deep plane conditions. Centered at l = [FORMULA] b = [FORMULA] it contains 128 sources above a maximum likelihood of 8 in a [FORMULA] area. The overall log N([FORMULA] S)-log S function is fully consistent with that derived from the Einstein galactic plane surveys having similar X-ray sensitivity (Hertz & Grindlay 1984) and with the results of deep ROSAT pointings (Morley et al. 1996). Thanks to a high completeness of optical identifications we are in a position to discuss the relative contributions of various kinds of X-ray sources. An overwhelming fraction of X-ray sources are identified with late type active coronae. Our identified sample exhibits the X-ray luminosity distribution expected in a flux limited survey and we detect F-G stars up to [FORMULA] 300 pc while M stars are not found beyond [FORMULA] 100 pc. X-ray count models account satisfactorily both for the observed log N([FORMULA] S)-log S relation and for the distribution in spectral types and suggest that most of the stars detected by ROSAT in this low latitude region are probably younger than 1 Gyr. We also put strong constraints on the possible contributions of old neutron stars accreting from the interstellar medium and discuss the possible implications of our results.

Previous Section Next Section Title Page Table of Contents

© European Southern Observatory (ESO) 1997

Online publication: July 8, 1998