The authors would like to thank A. Fiedler for software support and T. Will for his data of RXJ0019. We are grateful to V. Burwitz and R. Popham for some helpful remarks on an earlier draft of this paper. We are grateful to E. Meyer-Hofmeister, F. Meyer and H. Ritter for helpful discussions. BD is especially grateful to H. Spruit for his assistance at MPA. We also thank the referee K. Matsumoto for valuable remarks.
© European Southern Observatory (ESO) 1999
Online publication: March 1, 1999