We would like to thank Dr. A.P. Fairall for the careful review of this manuscript and to Dr. H. Hagen for his contribution during the work with the HS data base. We also thank Dr. S. Pustil'nik for providing us some unpublished data on Markarian galaxies. We gratefully acknowledge the comments and discussions with Drs. B. Binggeli, A. Burkert, R. P Kirshner, D. Thompson, D. Valls-Gebaud. We would also like to thank the Calar Alto staff for their support during the observations. U. Hopp acknowledge the support by the SFB 375 by the Deutsche Forschungsgemeinschaft.
© European Southern Observatory (ESO) 1997
Online publication: March 26, 1998