A journey through the center of galaxies: formation and evolution of galactic nuclei around massive black holes
Fabio Antonini (CITA ) - November 25, 2013 at 12:10 pm
The center of stellar spheroids are often marked by the presence of nucleated central regions, called nuclear star clusters (NSCs). In this talk I will focus on the processes that lead to the formation of NSCs at the center of galaxies and discuss the long-term dynamical evolution of NSCs around massive black holes (MBHs). I will show that a NSC formation model in which massive globular clusters spiral to the center of a galaxy and merge to form a compact stellar system, reproduces the observed relation between the NSC masses (M) and the velocity dispersion (sigma) of their host galaxies, the M sigma relation. Such a dissipationless formation model is also in agreement with the observed half-mass-radius vs mass relation for NSCs, and is consistent with the absence of NSCs in the brightest galaxies. I will conclude with presenting the results from a set of N-body simulations which model the reapeted merger of globular clusters into the center of the Milky Way. After about ten inspiral events, many properties of the Galactic NSC, including its mass, density profile and luminosity function, are reproduced. A scenario in which a large fraction of the mass of the Milky Way NSC is due to infalling globular clusters is therefore consistent with existing observational constraints.
The seminar will be held in B-1 Hearst Field Annex.
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