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Astron. Astrophys. 355, 873-879 (2000) AcknowledgementsWe thank Jim Pringle for insightful suggestions and Edo Trussoni for useful comments on the manuscript. The authors acknowledge the Italian MURST for financial support. This research was supported in part by the National Science Foundation under Grant No. PHY94-07194 (A. Celotti). This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
© European Southern Observatory (ESO) 2000 Online publication: March 21, 2000 ![]() |