4 Summary

  The EXMS, a new catalog of X-ray detections derived from observations made by EXOSAT during slew manoeuvres between 1983 and 1986, is presented. Where possible, detections are identified with cataloged sources and the raw count rates corrected for collimator losses. Many types of object are detected, although X-ray binaries constitute the most common identification. The catalog has been shown to be free of obvious systematic errors and to contain reliable count rates for time-invariant sources. An electronic version of this catalog is maintained within the EXOSAT database and archive system at ESTEC (telnet://xray@exosat.estec.esa.nl).

The catalog contains new data on the long-term time variability of many well known sources and in particular on X-ray binaries. 95 different X-ray binaries appear in Table 3; roughly half of all X-ray binaries which have ever been detected. All of the expected X-ray binaries were seen, many of them repeatedly. We note that the transient source EXO0748-676 appears as an EXMS source several times before it was actually detected in February 1985. Repeated source detections tend to be grouped at six monthly intervals due to the way in which EXOSAT slewed (see Sect. 1). For instance, Ser X-1 (Fig. 20) was detected on 15 occasions between 1983/279 and 1985/278, on nine separate days in five clusters each spaced by six months. Lightcurves for the XRBs 4U0918-549 and LMC X-3 are presented in Figs. 21-22, together with brief comments.

Acknowledgements

We thank H. Siddiqui, A. Hazell, K. Bennett and E. Kuulkers. F. Ochsenbein of the Observatoire Astronomique de Strasbourg is thanked for help on the EXMS naming policy. In addition to the online databases at ESTEC, this research made use of data obtained from the High Energy Astrophysics Science Archive Research Center, provided by the NASA-Goddard Space Flight Center. We thank the referee, Dr. W. Voges, for many helpful suggestions.