On the transition from nuclear-cluster- to black-hole dominated galaxy cores

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Bekki, Kenji

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On the transition from nuclear-cluster- to black-hole dominated galaxy cores

Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/85999

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Title: On the transition from nuclear-cluster- to black-hole dominated galaxy cores
Author(s): Bekki, Kenji; Graham, Alister W.
Abstract: Giant elliptical galaxies, believed to be built from the merger of lesser galaxies, are known to house a massive black hole (MBH) at their center rather than a compact star cluster. If low-and intermediate-mass galaxies do indeed partake in the hierarchical merger scenario, then one needs to explain why their dense nuclear star clusters are not preserved in merger events. A valuable clue may be the recent revelation that nuclear star clusters and MBHs frequently co-exist in intermediate-mass bulges and elliptical galaxies. In an effort to understand the physical mechanism responsible for the disappearance of nuclear star clusters, we have numerically investigated the evolution of merging star clusters with seed BHs. Using BHs that are 1%-5% of their host nuclear cluster mass, we reveal how their binary coalescence during a merger dynamically heats the newly wed star cluster, expanding it, significantly lowering its central stellar density, and thus making it susceptible to tidal destruction during galaxy merging. Moreover, this mechanism provides a pathway to explain the observed reduction in the nucleus-to-galaxy stellar mass ratio as one proceeds from dwarf to giant elliptical galaxies.
Publication type: Journal article
Research centre: Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing
Source: Astrophysical Journal Letters, Vol. 714, no. 2 (May 2010), pp. L313-L317
Publication year: 2010
FOR Code(s): 0201 Astronomical and Space Sciences
Keyword(s): Black hole physics; Galaxy evolution; Galaxy nuclei; Galaxy structure
Publisher: Institute of Physics Publishing
ISSN: 2041-8205
Publisher URL: http://dx.doi.org/10.1088/2041-8205/714/2/l313
Peer reviewed