Evolution of nuclear star clusters

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dc.contributor.author Merritt, David
dc.date.accessioned 2009-02-25T18:14:38Z
dc.date.available 2009-02-25T18:14:38Z
dc.date.issued 2009-01-05
dc.identifier.citation arXiv:0802.3186v2 [astro-ph] en_US
dc.identifier.uri http://hdl.handle.net/1850/8507
dc.description Archived in arXiv:0802.3186 v2 Jan 5, 2009. en_US
dc.description.abstract Two-body relaxation times of nuclear star clusters are short enough that gravitational encounters should substantially affect their structure in 10 Gyr or less. In nuclear star clusters without massive black holes, dynamical evolution is a competition between core collapse, which causes densities to increase, and heat input from the surrounding galaxy, which causes densities to decrease. The maximum extent of a nucleus that can resist expansion is derived numerically for a wide range of initial conditions; observed nuclei are shown to be compact enough to resist expansion, although there may have been an earlier generation of low-density nuclei that were dissolved. An evolutionary model for NGC 205 is presented which suggests that the nucleus of this galaxy has already undergone core collapse. Adding a massive black hole to a nucleus inhibits core collapse, and nuclear star clusters with black holes always expand, due primarily to heat input from the galaxy and secondarily to heating from stellar disruptions. The expansion rate is smaller for larger black holes due to the smaller temperature difference between galaxy and nucleus when the black hole is large. The rate of stellar tidal disruptions and its variation with time are computed for a variety of initial models. The disruption rate generally decreases with time due to the evolving nuclear density, particularly in the faintest galaxies, assuming that scaling relations derived for luminous galaxies can be extended to low luminosities. en_US
dc.language.iso en_US en_US
dc.publisher arXiv - eprints en_US
dc.relation RIT Scholars content from RIT Digital Media Library has moved from http://ritdml.rit.edu/handle/1850/8507 to RIT Scholar Works http://scholarworks.rit.edu/article/138, please update your feeds & links!
dc.subject Galaxies: dynamics en_US
dc.subject Galaxies: evolution en_US
dc.subject Galaxies: nuclei en_US
dc.title Evolution of nuclear star clusters en_US
dc.type Article en_US

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