Acknowledgements

We thank the staff of Mount Stromlo and Siding Spring Observatories and of the Australia Telescope National Facility for their assistance during and after the observations. We also thank A. Bosma and A. Kalnajs for useful discussions, and the referees for their helpful comments. M. Bureau acknowledges the support of an Australian DEET Overseas Postgraduate Research Scholarship and a Canadian NSERC Postgraduate Scholarship.

The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.

© Copyright Astronomical Society of Australia 1997