It is a pleasure to thank Hans Böhringer, Makoto Hattori, Andreas Huss, and Doris Neumann for helpful discussions. We also thank Leopoldo Infante for providing unpublished galaxy data to us, and Edmond Giraud for providing us with the unpublished redshift of the arc in Cl 0500-24. We acknowledge valuable comments by Jean-Paul Kneib which helped to improve the paper considerably. S.S. acknowledges financial support by the Verbundforschung.
© European Southern Observatory (ESO) 1997
Online publication: June 30, 1998