Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes

In this study, we investigate the impact of modified gravity (MG) on the merger rate of compact binaries within dark matter spikes surrounding supermassive black holes (SMBHs). Specifically, we calculate the binary merger rates involving primordial black holes (PBHs) and/or neutron stars (NSs) in Hu...

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Main Authors: Saeed Fakhry, Sara Gholamhoseinian, Marzieh Farhang
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ad8917
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author Saeed Fakhry
Sara Gholamhoseinian
Marzieh Farhang
author_facet Saeed Fakhry
Sara Gholamhoseinian
Marzieh Farhang
author_sort Saeed Fakhry
collection DOAJ
description In this study, we investigate the impact of modified gravity (MG) on the merger rate of compact binaries within dark matter spikes surrounding supermassive black holes (SMBHs). Specifically, we calculate the binary merger rates involving primordial black holes (PBHs) and/or neutron stars (NSs) in Hu–Sawicki f ( R ) gravity and the normal branch of Dvali–Gabadadze–Porrati (nDGP) gravity, with three SMBH mass functions: Benson, Vika, and Shankar. The results show consistently higher merger rates predicted for PBH–PBH and PBH–NS binaries in these gravity models compared to general relativity (GR), in particular at lower SMBH masses and for steeper dark matter spike density profiles. The predicted merger rates are compared to the LIGO–Virgo–KAGRA observations in constraining the parameters of the theory. In particular, we find steeper dark matter spike density profiles in the MG scenarios compared to GR. When compared to current observational constraints on PBH abundance, the mass ranges allowed by Hu–Sawicki f ( R ) models are found to be wider than those allowed by nDGP models, for given merger rates. The results are highly dependent on the choice of SMBH mass function, with the Vika and Shankar mass functions predicting lower abundances. The considerable sensitivity of the results to the assumed gravity scenario and SMBH mass function demonstrates the necessity of incorporating the corresponding theoretical uncertainties when making relatively robust predictions on compact binary merger rates and, as a result, on PBH properties.
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spelling doaj-art-b2e3cc44d96045cea17adcead54dd6e62025-08-20T02:05:29ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01976224810.3847/1538-4357/ad8917Compact Binary Merger Rate with Modified Gravity in Dark Matter SpikesSaeed Fakhry0https://orcid.org/0000-0002-6349-8489Sara Gholamhoseinian1Marzieh Farhang2Department of Physics, Shahid Beheshti University , 1983969411, Tehran, Iran ; s_fakhry@sbu.ac.ir, s.gholamhoseinian@gmail.com, m_farhang@sbu.ac.irDepartment of Physics, Shahid Beheshti University , 1983969411, Tehran, Iran ; s_fakhry@sbu.ac.ir, s.gholamhoseinian@gmail.com, m_farhang@sbu.ac.irDepartment of Physics, Shahid Beheshti University , 1983969411, Tehran, Iran ; s_fakhry@sbu.ac.ir, s.gholamhoseinian@gmail.com, m_farhang@sbu.ac.irIn this study, we investigate the impact of modified gravity (MG) on the merger rate of compact binaries within dark matter spikes surrounding supermassive black holes (SMBHs). Specifically, we calculate the binary merger rates involving primordial black holes (PBHs) and/or neutron stars (NSs) in Hu–Sawicki f ( R ) gravity and the normal branch of Dvali–Gabadadze–Porrati (nDGP) gravity, with three SMBH mass functions: Benson, Vika, and Shankar. The results show consistently higher merger rates predicted for PBH–PBH and PBH–NS binaries in these gravity models compared to general relativity (GR), in particular at lower SMBH masses and for steeper dark matter spike density profiles. The predicted merger rates are compared to the LIGO–Virgo–KAGRA observations in constraining the parameters of the theory. In particular, we find steeper dark matter spike density profiles in the MG scenarios compared to GR. When compared to current observational constraints on PBH abundance, the mass ranges allowed by Hu–Sawicki f ( R ) models are found to be wider than those allowed by nDGP models, for given merger rates. The results are highly dependent on the choice of SMBH mass function, with the Vika and Shankar mass functions predicting lower abundances. The considerable sensitivity of the results to the assumed gravity scenario and SMBH mass function demonstrates the necessity of incorporating the corresponding theoretical uncertainties when making relatively robust predictions on compact binary merger rates and, as a result, on PBH properties.https://doi.org/10.3847/1538-4357/ad8917Cold dark matterPrimordial black holesGravitationGravitational wavesNeutron stars
spellingShingle Saeed Fakhry
Sara Gholamhoseinian
Marzieh Farhang
Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes
The Astrophysical Journal
Cold dark matter
Primordial black holes
Gravitation
Gravitational waves
Neutron stars
title Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes
title_full Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes
title_fullStr Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes
title_full_unstemmed Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes
title_short Compact Binary Merger Rate with Modified Gravity in Dark Matter Spikes
title_sort compact binary merger rate with modified gravity in dark matter spikes
topic Cold dark matter
Primordial black holes
Gravitation
Gravitational waves
Neutron stars
url https://doi.org/10.3847/1538-4357/ad8917
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AT saragholamhoseinian compactbinarymergerratewithmodifiedgravityindarkmatterspikes
AT marziehfarhang compactbinarymergerratewithmodifiedgravityindarkmatterspikes