The rotation curve of the Local Group spiral M33 has been studied out to large distances from the center, providing strong evidence for the existence of dark matter. Galaxies without a strong central mass concentration such as a stellar bulge or massive black hole have been studied in recent years to test theoretical predictions of the inner structure of dark matter halos. M33, as the closest "pure disk" system, is one of the principal galaxies for this type of test. I will discuss recent results on the kinematics of stars and gas in the inner kpc in M33. The kinematics turn out to be surprisingly complex, with evidence for non-radial motions in the gas pointing strongly to the existence of a weak bar or triaxial bulge. This now seems to imply that the four major Local Group Galaxies are all barred galaxies. I will discuss the general properties of the central region, the previously presented evidence for a bar or bulges from photometric studies, and the (lack of) evidence for a central massive black hole in M33. It is not obvious that the effects we see in M33 would be easily recognized in more distant galaxies. Hence, the question of the central structure of dark matter halo profiles may not be easily settled.

March 30, 2007
11:00 a.m. MT

Array Operations Center Auditorium

All NRAO employees are invited to attend via video, available in Charlottesville Room 230, Green Bank Room 137 and Tucson 525.

Local Host: Michael Rupen