Black Hole Accretion and Spin-up Through Stellar Collisions in Dense Star Clusters

Fuente: arXiv
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Auteurs principaux: Kıroğlu, Fulya, Kremer, Kyle, Biscoveanu, Sylvia, Prieto, Elena González, Rasio, Frederic A.
Format: Preprint
Publié: 2024
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author Kıroğlu, Fulya
Kremer, Kyle
Biscoveanu, Sylvia
Prieto, Elena González
Rasio, Frederic A.
author_facet Kıroğlu, Fulya
Kremer, Kyle
Biscoveanu, Sylvia
Prieto, Elena González
Rasio, Frederic A.
contents Dynamical interactions in dense star clusters could significantly influence the properties of black holes, leaving imprints on their gravitational-wave signatures. While previous studies have mostly focused on repeated black hole mergers for spin and mass growth, this work examines the impact of physical collisions and close encounters between black holes and (non-compact) stars. Using Monte Carlo N-body models of dense star clusters, we find that a large fraction of black holes retained upon formation undergo collisions with stars. Within our explored cluster models, the proportion of binary black hole mergers affected by stellar collisions ranges from $10\%$ to $60\%$. If all stellar-mass black holes are initially non-spinning, we find that up to $40\%$ of merging binary black holes may have components with dimensionless spin parameter $χ\gtrsim 0.2$ because of prior stellar collisions, while typically about $10\%$ have spins near $χ= 0.7$ from prior black hole mergers. We demonstrate that young star clusters are especially important environments as they can produce collisions of black holes with very massive stars, allowing significant spin up of the black holes through accretion. Our predictions for black hole spin distributions from these stellar collisions highlight their sensitivity to accretion efficiency, underscoring the need for detailed hydrodynamic calculations to better understand the accretion physics following these interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2410_01879
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Black Hole Accretion and Spin-up Through Stellar Collisions in Dense Star Clusters
Kıroğlu, Fulya
Kremer, Kyle
Biscoveanu, Sylvia
Prieto, Elena González
Rasio, Frederic A.
High Energy Astrophysical Phenomena
Dynamical interactions in dense star clusters could significantly influence the properties of black holes, leaving imprints on their gravitational-wave signatures. While previous studies have mostly focused on repeated black hole mergers for spin and mass growth, this work examines the impact of physical collisions and close encounters between black holes and (non-compact) stars. Using Monte Carlo N-body models of dense star clusters, we find that a large fraction of black holes retained upon formation undergo collisions with stars. Within our explored cluster models, the proportion of binary black hole mergers affected by stellar collisions ranges from $10\%$ to $60\%$. If all stellar-mass black holes are initially non-spinning, we find that up to $40\%$ of merging binary black holes may have components with dimensionless spin parameter $χ\gtrsim 0.2$ because of prior stellar collisions, while typically about $10\%$ have spins near $χ= 0.7$ from prior black hole mergers. We demonstrate that young star clusters are especially important environments as they can produce collisions of black holes with very massive stars, allowing significant spin up of the black holes through accretion. Our predictions for black hole spin distributions from these stellar collisions highlight their sensitivity to accretion efficiency, underscoring the need for detailed hydrodynamic calculations to better understand the accretion physics following these interactions.
title Black Hole Accretion and Spin-up Through Stellar Collisions in Dense Star Clusters
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2410.01879