We would like to thank the staff of the UKST, especially Quentin Parker, Ken Russell, Malcom Hartley, and Fred Watson for excellent support during our observations. We are grateful to Scott Wolk for stimulating discussions. This work was supported by the DARA under grant 05 OR 9103 0 and by the DFG under grant Yo 5/18-1,2. TP, SF, and MS acknowledge grants from the DFG "Physik der Sternentstehung" Program. The ROSAT project was supported by the Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie (BMBF/DARA) and the Max-Planck-Society. The use of the Astrophysics Data System (ADS) provided by NASA, the SIMBAD database operated at CDS, and the Digitized Sky Survey provided by the Space Telescope Science Institute is acknowledged.
© European Southern Observatory (ESO) 1998
Online publication: April 20, 1998