Dynamical evolution of black hole subsystems in idealized star clusters

By Philip G. Breen, Douglas Heggie. 2013

152 citations recorded by the source corpus.

In this paper, globular star clusters which contain a sub-system of stellar-mass black holes (BH) are investigated. This is done by considering two-component models, as these are the simplest approximation of more realistic multi-mass systems, where one component represents the BH population and the other represents all the other stars. These systems are found to undergo a long phase of evolution where the centre of the system is dominated by a dense BH sub-system. After mass segregation has driven most of the BH into a compact sub-system, the evolution of the BH sub-system is found to be influenced by the cluster in which it is contained. The BH sub-system evolves in such a way as to satisfy the energy demands of the whole cluster, just as the core of a one component system must satisfy the energy demands of the whole cluster. The BH sub-system is found to exist for a significant amount of time. It takes approximately 10t_{rh,i}, where t_{rh,i} is the initial half-mass relaxation time, from the formation of the compact BH sub-system up until the time when 90% of the sub-system total mass is lost (which is of order 10^{3} times the half-mass relaxation time of the BH sub-system at its time of formation). Based on theoretical arguments the rate of mass loss from the BH sub-system (\dot{M}_2) is predicted to be -(beta*zeta*M)/(alpha*t_{rh}), where M is the total mass, t_{rh} is the half-mass relaxation time, and alpha, beta, zeta are three dimensionless parameters (see Section 2 for details). An interesting consequence of this is that the rate of mass loss from the BH sub-system is approximately independent of the stellar mass ratio (m_2/m_1) and the total mass ratio (M_2/M_1) (in the range m_2/m_1 >~ 10 and M_2/M_1 ~ 10^{-2}, where m_1, m_2 are the masses of individual low-mass and high-mass particles respectively, and M_1, M_2 are the corresponding total masses).

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/2185af71e9165c7309e5427bf275ba8f1d750b85

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Citations in the corpus

Modeling Dense Star Clusters in the Milky Way and Beyond with the CMC Cluster Catalog (2019, background): “…a consequence of mass segregation and is consistent with predictions from a number of recent analyses (e.g., Kulkarni et al. 1993; Sigurdsson 1993; Breen & Heggie 2013; 8 The Astrophysical Journal Supplement Series, 247:48 (44pp), 2020 April Kremer et al. Morscher et al. 2015; Chatterjee et al.…”
Black hole growth through hierarchical black hole mergers in dense star clusters: implications for gravitational wave detections (2018, background): “This means that the heat production in the centre by BHs is balanced by the global energy flow (Hénon 1961; Gieles et al. 2011; Breen & Heggie 2013) and we can relate the heat generation to the cluster properties: ÛE = ζ |E | τrh , (1) where E ≃ −0.2GM2 cl /rh is the total energy of the cluster,…”
One Channel to Rule Them All? Constraining the Origins of Binary Black Holes Using Multiple Formation Pathways (2020, methodology): “In this method, we assume that the energy generated by the BH binaries in the cluster core is regulated by the process of two-body relaxation in the bulk of the system (Breen & Heggie 2013).”
CO-EVOLUTION OF GALACTIC NUCLEI AND GLOBULAR CLUSTER SYSTEMS (2013, background): “If the energy generated in three-body encounters between binary and single black holes is efficiently transferred to the velocities of main-sequence stars, corecollapse could be delayed by several relaxation times, until all black holes are gradually ejected (Breen & Heggie 2013b).”
Constraining Stellar-mass Black Hole Mergers in AGN Disks Detectable with LIGO (2017, background): “While BHs with larger than expected masses can occur naturally in the field (Belczynski et al. 2010; deMink & Mandel 2016) and in globular clusters (Breen & Heggie 2013; Rodriguez et al. 2016a, 2018; Wang et al. 2016), they are more likely to form in regions with concentrations of BHs, such as…”
The dragon simulations: globular cluster evolution with a million stars (2016, methodology): “…and black holes) are not only interesting for X-ray, radio and gravitational wave observations, but also have significant influence on the dynamical evolution of GCs (e.g. Downing 2012; Hurley 2007; Breen & Heggie 2013; Morscher et al. 2015; Contenta, Varri, & Heggie 2015; Giersz et al. 2015).”
THE DYNAMICAL EVOLUTION OF STELLAR BLACK HOLES IN GLOBULAR CLUSTERS (2014, methodology): “In Figure 1, we compare the cluster properties as reported by the N -body simulations of Breen & Heggie (2013) to those computed by our MC code.”
Stellar-mass black holes in young massive and open stellar clusters and their role in gravitational-wave generation (2016, background): “MNRAS 000, 1–17 (2016) energy generation due to dynamical encounters within the BH-core inside a stellar cluster, as recently done in the semianalytic study by Breen & Heggie (2013a).”
The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes (2014, background): “Work for many years has found that the holes would sink into a dense subcluster and self-eject [18, 19, 20, 21, 22], but the recent discovery of black hole candidates in several globular clusters [23, 24, 25, 26, 27, 28] has led to re-examination of globular cluster black hole dynamics [29, 30, 31, ”
A detached stellar-mass black hole candidate in the globular cluster NGC 3201 (2018, result): “In fact, state-of-the art models for clusters do predict that the retention fractions of black holes might be significantly enhanced compared to the earlier studies mentioned above (e.g. Breen & Heggie 2013; Morscher et al. 2013).”