Merger rates in primordial black hole clusters without initial binaries
(2020) In Monthly Notices of the Royal Astronomical Society 496(1). p.994-1000- Abstract
Primordial black holes formed through the collapse of cosmological density fluctuations have been hypothesized as contributors to the dark matter content of the Universe. At the same time, their mergers could contribute to the recently observed population of gravitational-wave sources. We investigate the scenario in which primordial black holes form binaries at late times in the Universe. Specifically, we re-examine the mergers of primordial black holes in small clusters of ∼30 objects in the absence of initial binaries. Binaries form dynamically through Newtonian gravitational interactions. These binaries act as heat sources for the cluster, increasing the cluster's velocity dispersion, which inhibits direct mergers through... (More)
Primordial black holes formed through the collapse of cosmological density fluctuations have been hypothesized as contributors to the dark matter content of the Universe. At the same time, their mergers could contribute to the recently observed population of gravitational-wave sources. We investigate the scenario in which primordial black holes form binaries at late times in the Universe. Specifically, we re-examine the mergers of primordial black holes in small clusters of ∼30 objects in the absence of initial binaries. Binaries form dynamically through Newtonian gravitational interactions. These binaries act as heat sources for the cluster, increasing the cluster's velocity dispersion, which inhibits direct mergers through gravitational-wave two-body captures. Meanwhile, three-body encounters of tight binaries are too rare to tighten binaries sufficiently to allow them to merge through gravitational-wave emission. We conclude that in the absence of initial binaries, merger rates of primordial black holes in the considered scenario are at least an order of magnitude lower than previously suggested, which makes gravitational-wave detections of such sources improbable.
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- author
- Korol, Valeriya ; Mandel, Ilya ; Coleman Miller, M. ; Church, Ross P. LU and Davies, Melvyn B. LU
- organization
- publishing date
- 2020
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- black hole mergers, cosmology: dark matter, gravitational waves
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 496
- issue
- 1
- pages
- 7 pages
- publisher
- Oxford University Press
- external identifiers
-
- scopus:85088587822
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/staa1644
- language
- English
- LU publication?
- yes
- id
- fbf41554-bbd4-4264-a5d4-69433706947d
- date added to LUP
- 2020-08-05 09:10:56
- date last changed
- 2024-04-17 13:15:51
@article{fbf41554-bbd4-4264-a5d4-69433706947d, abstract = {{<p>Primordial black holes formed through the collapse of cosmological density fluctuations have been hypothesized as contributors to the dark matter content of the Universe. At the same time, their mergers could contribute to the recently observed population of gravitational-wave sources. We investigate the scenario in which primordial black holes form binaries at late times in the Universe. Specifically, we re-examine the mergers of primordial black holes in small clusters of ∼30 objects in the absence of initial binaries. Binaries form dynamically through Newtonian gravitational interactions. These binaries act as heat sources for the cluster, increasing the cluster's velocity dispersion, which inhibits direct mergers through gravitational-wave two-body captures. Meanwhile, three-body encounters of tight binaries are too rare to tighten binaries sufficiently to allow them to merge through gravitational-wave emission. We conclude that in the absence of initial binaries, merger rates of primordial black holes in the considered scenario are at least an order of magnitude lower than previously suggested, which makes gravitational-wave detections of such sources improbable.</p>}}, author = {{Korol, Valeriya and Mandel, Ilya and Coleman Miller, M. and Church, Ross P. and Davies, Melvyn B.}}, issn = {{0035-8711}}, keywords = {{black hole mergers; cosmology: dark matter; gravitational waves}}, language = {{eng}}, number = {{1}}, pages = {{994--1000}}, publisher = {{Oxford University Press}}, series = {{Monthly Notices of the Royal Astronomical Society}}, title = {{Merger rates in primordial black hole clusters without initial binaries}}, url = {{http://dx.doi.org/10.1093/mnras/staa1644}}, doi = {{10.1093/mnras/staa1644}}, volume = {{496}}, year = {{2020}}, }