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arXiv · 2404.08735

Primordial black holes captured by neutron stars: relativistic point-mass treatment

Thomas W. Baumgarte·Stuart L. Shapiro
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Abstract

Primordial black holes (PBHs), if they exist, may collide with and be captured by neutron stars. We adopt a relativistic point-mass approximation to study this capture, the subsequent confinement of the PBH of mass $m$ inside the neutron star of mass $M_* \gg m$, and the PBH's growth by accretion of stellar material. Building on earlier treatments we systematically study the capture, confinement, and accretion process, characterize the emitted quasiperiodic continuous gravitational-wave signal, track the evolution of the PBH's orbital parameters, and compare the effects of different choices for the prescription of the dissipative forces. Our point-mass treatment here is applicable in the limit of small PBH masses, for which its effects on the neutron star can be ignored.

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Thomas W. Baumgarte, Stuart L. Shapiro. 2024-04-12. Primordial black holes captured by neutron stars: relativistic point-mass treatment. https://doi.org/10.1103/physrevd.109.123012

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