![]() | ![]() |
Astron. Astrophys. 363, 455-475 (2000) AcknowledgementsThis work was partly supported by the Italian Ministry for University and Research (MURST) under grant Cofin98-02-32 ![]() ![]() ![]() ![]() © European Southern Observatory (ESO) 2000 Online publication: December 11, 2000 ![]() |