The all-sky survey and the pointed observations during the ROSAT mission have enabled the detection of more than 150.000 new X-ray sources which is a factor of more than 20 as compared to the number of sources known before ROSAT. The source lists were produced automatically by the Standard Analysis Software System (SASS). For each X-ray source the following source properties are calculated: detection likelihood, source position in celestial co-ordinates, source and local background count-rates, exposure time, power law index, temperature and column density, hardness ratios, source extent and corresponding likelihood, and temporal variability flags. To produce reliable source catalogues, further visual screening was performed.

The ROSAT collaboration is currently screening the SASS source lists from pointed observations with the PSPC and the HRI to provide catalogues for the ROSAT Results Archive.

ROSAT all-sky survey maps of the diffuse X-ray background are produced in up to 7 energy bands, and having various angular resolutions between 12' and 40' with and without point-source exclusion. The first set of maps can be accessed electronically; other maps will follow.

1 this source list is the basis for the RASS-BSC, and RASS-FSC catalogues.

2 every source visually screened; other selection criteria: count-rate cts/s and counts ; source list contains flags partly set automatically or by visual inspection. 603 pixel images of flagged sources can be accessed electronically. Accuracy of source position: arcsec (). To identify the ROSAT sources optical follow-up observations and cross-correlations with existing catalogues such as SIMBAD, NED, TYCHO, FIRST, NVSS, and HQS have been performed. About 30% have a probable identification candidate. The SLOAN digital sky survey (SDSS) will help identifying sources.

3 sources which were obviously false detections residing in extended emission regions like SNRs, galaxy clusters, and very bright sources have been screened out manually (input list for SDSS).

4 based on the source lists of the all-sky survey and pointing data.

References:

Voges, W., Aschenbach, B., Boller, Th., Bräuninger, H., Briel, U., Burkert, W., Dennerl, K., Englhauser, J., Gruber, R., Haberl, F., Hartner, G., Hasinger, G., Kürster, M., Pfeffermann, E., Pietsch, W., Predehl, P., Rosso, C., Schmitt, J.H.M.M., Trümper, J., & Zimmermann, H.U.: The ROSAT All-Sky Survey bright source catalogue, to be published in A&AS (1997)

Snowden, S.L., M.J. Freyberg, P.P. Plucinsky, J.H.M.M. Schmitt, J. Trümper, W. Voges, R.J. Edgar, D. McCammon and W.T. Sanders: First Maps of the Soft X-Ray Diffuse Background from the ROSAT XRT/PSPC All-Sky Survey, Astrophys.Journ., 454, 643-653 (1995).

Snowden, S.L., R. Egger, M.J. Freyberg, D. McCammon, P.P. Plucinsky, W.T. Sanders, J.H.M.M. Schmitt, J. Trümper and W. Voges: ROSAT Survey Diffuse X-Ray Background Maps. II., Astrophys.Journ., 485, 125-135 (1997a).

Snowden, S.L., R. Egger, D.P. Finkbeiner, M.J. Freyberg and P.P. Plucinsky: Progress on establishing the spatial distribution of material responsible for the 1/4 keV SXRB, local and halo components, Astrophys.Journ., in press (1997b).

Wolfgang Voges (wvoges@mpe.mpg.de)
Max-Planck-Institut für extraterrestrische Physik
Giessenbachstr.1 , D-85740 Garching , Germany
Tel: +49-89-3299-3572, Fax: +49-89-3299-3569
Office: 392