Lower-mass-gap Black Holes in Dense Star Clusters

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Ye, Claire S., Kremer, Kyle, Ransom, Scott M., Rasio, Frederic A.
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866929573514444800
author Ye, Claire S.
Kremer, Kyle
Ransom, Scott M.
Rasio, Frederic A.
author_facet Ye, Claire S.
Kremer, Kyle
Ransom, Scott M.
Rasio, Frederic A.
contents The existence of compact stellar remnants in the mass range $2-5\,M_{\odot}$ has long been debated. This so-called lower mass gap was initially suggested by the lack of low-mass X-ray binary observations with accretors about $2-5\,M_{\odot}$, but it has recently been called into question following newer observations, including a lower-mass-gap candidate with a millisecond pulsar companion in the dense globular cluster NGC 1851. Here we model NGC 1851 with a grid of similar dense star clusters utilizing the state-of-the-art Monte Carlo $N$-body code \texttt{CMC}, and we specifically study the formation of lower-mass-gap black holes. We demonstrate that both massive star evolution and dynamical interactions can contribute to forming lower-mass-gap black holes. In general, the collapse of massive remnants formed through mergers of neutron stars or massive white dwarfs produces the largest number of lower-mass-gap black holes among all formation channels. However, in more massive clusters, supernova core collapse can contribute comparable numbers. Our NGC 1851-like models can reproduce millisecond pulsar -- lower-mass-gap black hole binaries similar to the observed system. Additionally, the lower-mass-gap black holes can also become components of dynamically assembled binaries, and some will be in merging black hole - neutron star systems similar to the recently detected gravitational wave source GW230529. However, the corresponding merger rate is probably $\lesssim 1~{\rm Gpc^{-3}\,yr^{-1}}$.
format Preprint
id arxiv_https___arxiv_org_abs_2408_00076
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Lower-mass-gap Black Holes in Dense Star Clusters
Ye, Claire S.
Kremer, Kyle
Ransom, Scott M.
Rasio, Frederic A.
High Energy Astrophysical Phenomena
The existence of compact stellar remnants in the mass range $2-5\,M_{\odot}$ has long been debated. This so-called lower mass gap was initially suggested by the lack of low-mass X-ray binary observations with accretors about $2-5\,M_{\odot}$, but it has recently been called into question following newer observations, including a lower-mass-gap candidate with a millisecond pulsar companion in the dense globular cluster NGC 1851. Here we model NGC 1851 with a grid of similar dense star clusters utilizing the state-of-the-art Monte Carlo $N$-body code \texttt{CMC}, and we specifically study the formation of lower-mass-gap black holes. We demonstrate that both massive star evolution and dynamical interactions can contribute to forming lower-mass-gap black holes. In general, the collapse of massive remnants formed through mergers of neutron stars or massive white dwarfs produces the largest number of lower-mass-gap black holes among all formation channels. However, in more massive clusters, supernova core collapse can contribute comparable numbers. Our NGC 1851-like models can reproduce millisecond pulsar -- lower-mass-gap black hole binaries similar to the observed system. Additionally, the lower-mass-gap black holes can also become components of dynamically assembled binaries, and some will be in merging black hole - neutron star systems similar to the recently detected gravitational wave source GW230529. However, the corresponding merger rate is probably $\lesssim 1~{\rm Gpc^{-3}\,yr^{-1}}$.
title Lower-mass-gap Black Holes in Dense Star Clusters
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2408.00076