Resonant relaxation in globular clusters
Resonant relaxation has been discussed as an efficient process that changes the angular momenta of stars orbiting around a central supermassive black hole due to the fluctuating gravitational field of the stellar cluster. Other spherical stellar systems, such as globular clusters, exhibit a restrict...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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IOP Publishing
2019
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| _version_ | 1826303709054763008 |
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| author | Meiron, Y Kocsis, B |
| author_facet | Meiron, Y Kocsis, B |
| author_sort | Meiron, Y |
| collection | OXFORD |
| description | Resonant relaxation has been discussed as an efficient process that changes the angular momenta of stars orbiting around a central supermassive black hole due to the fluctuating gravitational field of the stellar cluster. Other spherical stellar systems, such as globular clusters, exhibit a restricted form of this effect where enhanced relaxation rate only occurs in the directions of the angular momentum vectors, but not in their magnitudes; this is called vector resonant relaxation (VRR). To explore this effect, we performed a large set of direct N-body simulations, with up to 512k particles (where k =1024) and ~500 dynamical times. Contrasting these simulations, which naturally include the collective effects, with Spitzer-style Monte Carlo simulations, which by design only exhibit two-body relaxation, we show that the temporal behavior of the angular momentum vectors in N-body simulations cannot be explained by two-body relaxation alone. VRR operates efficiently in globular clusters with N > 104. The fact that VRR operates in globular clusters may open a way to use powerful tools in statistical physics for their description. In particular, since the distribution of orbital planes relaxes much more rapidly than the distribution of the magnitude of angular momentum and the radial action, the relaxation process reaches an internal statistical equilibrium in the corresponding part of phase space while the whole cluster is generally out of equilibrium, in a state of quenched disorder. We point out the need to include effects of VRR in Monte Carlo simulations of globular clusters. |
| first_indexed | 2024-03-07T06:06:49Z |
| format | Journal article |
| id | oxford-uuid:ee237fdd-c14c-427d-8282-0564503b8506 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:06:49Z |
| publishDate | 2019 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | oxford-uuid:ee237fdd-c14c-427d-8282-0564503b85062022-03-27T11:30:26ZResonant relaxation in globular clustersJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ee237fdd-c14c-427d-8282-0564503b8506EnglishSymplectic ElementsIOP Publishing2019Meiron, YKocsis, BResonant relaxation has been discussed as an efficient process that changes the angular momenta of stars orbiting around a central supermassive black hole due to the fluctuating gravitational field of the stellar cluster. Other spherical stellar systems, such as globular clusters, exhibit a restricted form of this effect where enhanced relaxation rate only occurs in the directions of the angular momentum vectors, but not in their magnitudes; this is called vector resonant relaxation (VRR). To explore this effect, we performed a large set of direct N-body simulations, with up to 512k particles (where k =1024) and ~500 dynamical times. Contrasting these simulations, which naturally include the collective effects, with Spitzer-style Monte Carlo simulations, which by design only exhibit two-body relaxation, we show that the temporal behavior of the angular momentum vectors in N-body simulations cannot be explained by two-body relaxation alone. VRR operates efficiently in globular clusters with N > 104. The fact that VRR operates in globular clusters may open a way to use powerful tools in statistical physics for their description. In particular, since the distribution of orbital planes relaxes much more rapidly than the distribution of the magnitude of angular momentum and the radial action, the relaxation process reaches an internal statistical equilibrium in the corresponding part of phase space while the whole cluster is generally out of equilibrium, in a state of quenched disorder. We point out the need to include effects of VRR in Monte Carlo simulations of globular clusters. |
| spellingShingle | Meiron, Y Kocsis, B Resonant relaxation in globular clusters |
| title | Resonant relaxation in globular clusters |
| title_full | Resonant relaxation in globular clusters |
| title_fullStr | Resonant relaxation in globular clusters |
| title_full_unstemmed | Resonant relaxation in globular clusters |
| title_short | Resonant relaxation in globular clusters |
| title_sort | resonant relaxation in globular clusters |
| work_keys_str_mv | AT meirony resonantrelaxationinglobularclusters AT kocsisb resonantrelaxationinglobularclusters |