Procedures for the interactive analysis of point sources from the ROSAT XRT/PSPC all-sky survey.

The ROSAT mission performed the first imaging all-sky survey in soft X-rays (0.1 - 2.4 keV) in 1990-1991. During the survey, roughly 50000 sources were detected, most of them on a basis of only a few photons. The analysis of ROSAT all-sky survey point-source data involves additional complications when compared to the normal techniques used for pointed-observation data. The determination of the correct exposure time and the selection of the background region are examples of critical problems. A set of interactive techniques for the extraction of source and background photons is described. Preliminary results from the survey observation of the black-hole candidate LMC X-3 are presented.