No Supermassive Black Hole in M33?
David Merritt,*
Laura Ferrarese,
Charles L. Joseph
We observed the nucleus of M33, the third-brightest galaxy in the
Local Group, with the Space Telescope Imaging Spectrograph at a
resolution at least a factor of 10 higher than previously obtained.
Rather than the steep rise expected within the radius of gravitational
influence of a supermassive black hole, the random stellar velocities
showed a decrease within a parsec of the center of the galaxy. The
implied upper limit on the mass of the central black hole is only 3000 solar masses, about three orders of magnitude lower than the
dynamically inferred mass of any other supermassive black hole.
Detecting black holes of only a few thousand solar masses is
observationally challenging, but it is critical to establish how
supermassive black holes relate to their host galaxies, and which
mechanisms influence the formation and evolution of both.
Department of Physics and Astronomy, Rutgers University, New
Brunswick, NJ 08854, USA.
*
To whom correspondence should be addressed. E-mail:
merritt{at}physics.rutgers.edu
