THE INNER DYNAMICAL MASS ACROSS GALAXY MORPHOLOGY: A WEAK SCALING WITH TOTAL STELLAR MASS

We compile a sample of dispersion-supported and rotation-supported galaxies for which the dynamical mass enclosed at 500 pc can be measured. We find that this dynamical quantity increases only slowly with stellar mass (M-total(<500 pc) proportional to M-stars(0.16)) over similar to 9 decades in baryonic mass and similar to 3 in length scale, with a sudden upturn at the highest masses (M-stars greater than or similar to 10(10) M-circle dot). This upturn occurs for the earliest types (S0 and Sa) of disk galaxies, and is consistent with the "extra" mass within 500 pc being predominantly stellar. This sudden change may be indicative of different bulge formation mechanisms between early- and late-type disks. We also compare the data to the results of recent galaxy formation simulations. These broadly track the observed trend, with some tendency to put too much mass in the inner 500 pc, depending on the details of each simulation.