Clive G. Page
Leicester University, for the XMM SSC Consortium
XMM is the ESA's cornerstone X-ray Observatory, due for launch in 1999. It will provide unprecedented sensitivity over the 0.1 - 10 keV X-ray band with simultaneous coverage of the 2000 - 6000 Å optical/UV band from the co-aligned optical monitor (OM). XMM is likely to detect more than 50000 serendipitous X-ray sources each year. ESA's competition for the XMM Science Survey Centre was won by a consortium of European institutes led by Leicester University. The SSC will undertake the complete pipeline processing of XMM data, producing catalogues of all detected X-ray sources with spectra, light-curves, images, etc. The SSC will also cross-correlate X-ray detections with the OM images, astronomical catalogues, and other archival data. There will also be a follow-up and identification programme concentrating on the serendipitous X-ray detections. The results will be distributed to the observers by ESA, and (after the proprietary period) will be available to the whole community from the XMM science archive. The XMM science analysis software is being designed and produced jointly by the SSC and by the XMM Science Operations Centre at ESTEC. Requirements definition and design work started in April 1996. The baseline plan, maximising software re-use, is to use a modular tool-kit based on the FTOOLS approach and an event-driven pipe-line system. New software, likely to be written in Fortran 90, will be developed for some instrument-specific stages and for source-searching, one of the critical areas for the follow-up programme. Here we describe the new challenges posed by XMM data and highlight aspects of the software development strategy and design.