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M. Valluri (Chicago), C.L. Joseph, D. Merritt, R. Olling (Rutgers), STIS Team
We present an analysis of the HST/STIS data for the nucleus of M32. We find a very steep rise in the stellar velocity dispersions inside of ~0.2'', from \sigma~50 km/s at 0.2'' to \sigma~160 km/s at 0.02''. Our data are the first to clearly resolve this feature, which is strong evidence for a supermassive dark object. The distribution of line-of-sight stellar velocities (LOSVD) is strongly non-Gaussian near the galaxy center, with extended wings like those expected from stars near a BH. Because the stellar motions at these small radii are dominated by the central dark object rather than by the combined gravitational force of the other stars, we are able to place much stronger constraints on the mass of the black hole than in previous studies with lower spatial resolution. We present estimates based on a three-integral axisymmetric modelling algorithm for the mass of the black hole and the orbital kinematics of the stars.
Support for this work was provided to the STIS IDT by NASA.