*************************************************************************
   51117
   ASCA observations have been extremely powerful in discovering low-Lx
   active nuclei in a large number of spiral galaxies. The most
   spectacular example is for the Sbc galaxy NGC 4258: water maser
   measurements indicated the presence of a hidden massive black hole
   (MBH) of 10**7-8 solar masses (Miyoshi et al. 1995) and ASCA promptly
   discovered a low-Lx nuclear activity in this galaxy (Makishima et
   al.1994). On the other side, though most giant elliptical galaxies are
   believed to possess MBHs, nuclear activity is still elusive in these
   objects. This is a major unresolved puzzle. We propose then to observe
   the E galaxy NGC 3377 which is suspected to hide a ~10**8 MBH to search
   for hard X-ray nuclear activity and test current theoretical models
   like advection-dominated accretion disk models.
 *************************************************************************