MOCCA Survey Database I: Dissolution of tidally filling star clusters harbouring BH subsystems. (arXiv:1904.01227v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Giersz_M/0/1/0/all/0/1">Mirek Giersz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Askar_A/0/1/0/all/0/1">Abbas Askar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_L/0/1/0/all/0/1">Long Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hypki_A/0/1/0/all/0/1">Arkadiusz Hypki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leveque_A/0/1/0/all/0/1">Agostino Leveque</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spurzem_R/0/1/0/all/0/1">Rainer Spurzem</a>
We investigate the dissolution process for dynamically evolving star clusters
embedded in an external tidal field by exploring MOCCA Survey Database I, with
focus on the presence and evolution of a stellar-mass black hole subsystem. We
argue that the presence of a black hole subsystem can lead to the dissolution
of tidally filling star clusters and this can be regarded as a third type of
cluster dissolution mechanism, in addition to well known mechanisms connected
with strong mass loss due to stellar evolution and mass loss connected with the
relaxation process. This third process is characterized by abrupt cluster
dissolution connected with the loss of dynamical equilibrium. The abrupt
dissolution is powered by the strong energy generation from a massive
stellar-mass black hole subsystem accompanied by tidal stripping. Additionally,
we argue that such a mechanism should also work for even tidally underfilling
clusters with top-heavy IMF. Observationally, star clusters which undergo
dissolution powered by the third mechanism would look as ‘dark cluster’ i.e.
composed of stellar mass black holes surrounded by expanding halo of luminous
stars Banerjee and Kroupa (2011), and they should be different from ‘dark
clusters’ harbouring an intermediate mass black holes as discussed by Askar et
al (2017). An additional observational consequence of an operation of the third
dissolution mechanism should be larger than expected abundance of free floating
BHs in the Galactic halo.
We investigate the dissolution process for dynamically evolving star clusters
embedded in an external tidal field by exploring MOCCA Survey Database I, with
focus on the presence and evolution of a stellar-mass black hole subsystem. We
argue that the presence of a black hole subsystem can lead to the dissolution
of tidally filling star clusters and this can be regarded as a third type of
cluster dissolution mechanism, in addition to well known mechanisms connected
with strong mass loss due to stellar evolution and mass loss connected with the
relaxation process. This third process is characterized by abrupt cluster
dissolution connected with the loss of dynamical equilibrium. The abrupt
dissolution is powered by the strong energy generation from a massive
stellar-mass black hole subsystem accompanied by tidal stripping. Additionally,
we argue that such a mechanism should also work for even tidally underfilling
clusters with top-heavy IMF. Observationally, star clusters which undergo
dissolution powered by the third mechanism would look as ‘dark cluster’ i.e.
composed of stellar mass black holes surrounded by expanding halo of luminous
stars Banerjee and Kroupa (2011), and they should be different from ‘dark
clusters’ harbouring an intermediate mass black holes as discussed by Askar et
al (2017). An additional observational consequence of an operation of the third
dissolution mechanism should be larger than expected abundance of free floating
BHs in the Galactic halo.
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