We thank Dolf de Winter and Daniel Proga for fruitful discussions. Martin Groenewegen is thanked for useful comments on the manuscript, and Conor Nixon for his assistance during the observations at the AAT. The referee, Dr. R. Hanuschik, is thanked for his comments that helped improve the paper. The allocation of time on the Anglo-Australian Telescope was awarded by PATT, the United Kingdom allocation panel. This work was entirely funded by the Particle Physics and Astronomy Research Council of the United Kingdom. This research has made use of the Simbad database, operated at CDS, Strasbourg, France.
© European Southern Observatory (ESO) 1997
Online publication: July 8, 1998