![]() | ![]() |
Astron. Astrophys. 355, 629-638 (2000) AcknowledgementsWe thank the referee, Dr. K. Smith, for valuable comments and suggestions. The ROSAT project has been supported by the Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie and the Max-Planck-Gesellschaft. ![]() ![]() ![]() ![]() © European Southern Observatory (ESO) 2000 Online publication: March 9, 2000 ![]() |