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Paper: The Central Structure of Elliptical Galaxies and the Stellar-Dynamical Search for Supermassive Black Holes
Volume: 182, Galaxy Dynamics: A Rutgers Symposium
Page: 124
Authors: Kormendy, John
Abstract: Elliptical galaxies are divided into two types: galaxies with steep profiles that show no breaks in slope or that have extra light at small radii compared to a Sérsic function fit and galaxies that show a break from steep outer profiles to shallow inner profiles. These cuspy cores are important because they are a sign of undiscovered physical processes. Profiles with extra light near the center resemble predictions of starburst remnants formed in dissipative mergers. There is growing evidence for a dichotomy between (1) normal- and low-luminosity Es that rotate rapidly, that are nearly isotropic, oblate-spheroidal, and substantially flattened, that have disky-distorted isophotes, and that are coreless, and (2) giant Es that are essentially nonrotating, that are anisotropic, modestly triaxial, and not very flattened, that are boxy-distorted, and that have cuspy cores. Black hole (BH) search: Hubble Space Telescope (HST) observations confirm ground-based BH detections and show that mass measurements are remarkably robust. Detection of large proper motions near the Galactic center make it one of the best BH cases. Demographic results include the discovery of enough BH mass to account for quasar energetics and strong evidence that BH mass correlates with bulge luminosity. M 31 nucleus: New CFHT spectroscopy supports Tremaine's model that both nuclei are part of an eccentric disk of stars orbiting the BH. The BH is offset from the center of mass, confirming that mbh >= 3 × 10^7 Msun.
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