DDA 33rd Meeting, Mt. Hood, OR, April 2002
Session 3. Galaxy Centers
Monday, April 22, 2002, 1:40-3:50pm

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[3.03] Dynamics of Galactic Nuclei

M. Milosavljevic, D. Merritt (Rutgers U.)

Non-equilibrium dynamics of galaxies and cold dark matter (CDM) haloes is studied within the context of hierarchical structure formation. A variety of evidence suggests that first collapsed objects in the universe had cuspy central density profiles. We study the effects of successive merger generations on the concentration of matter in the cusps. We carried out large scale N-body simulations of mergers of both types of objects (galaxies, halos) in the presence of compact central components (massive black holes, dense stellar bulges). Massive black-hole binaries that form during mergers induce cumulative damage on the cusps, quantified in terms of ``mass deficit." Stellar mass deficits of early type galaxies observed with HST are found to be a few times larger than the masses of their central black holes over two decades in the latter. This can be interpreted as evidence for the formation of galaxy nuclei via hierarchical build-up of protogalactic fragments populated by black holes. We calculate the damage incurred by CDM cusps and provide upper limits on the densities of galaxy-size dark matter halos in the inner kiloparsec. We also study the response of CDM haloes to mergers of bulges and discuss implications on the origin of stellar spheroid scaling relations.

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Bulletin of the American Astronomical Society, 34, #3
© 2002. The American Astronomical Society.