Nonlinear evolution of the ergoregion instability: Turbulence, bursts of radiation, and black hole formation

Fuente: arXiv
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Main Authors: Siemonsen, Nils, East, William E.
Format: Preprint
Published: 2025
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author Siemonsen, Nils
East, William E.
author_facet Siemonsen, Nils
East, William E.
contents Spacetimes with an ergoregion that is not connected to a horizon are linearly unstable. While the linear regime has been studied in a number of settings, little is known about the nonlinear evolution of this ergoregion instability. Here, we investigate this by numerically evolving the unstable growth of a massless vector field in a rapidly spinning boson star in full general relativity. We find that the backreaction of the instability causes the star to become more gravitationally bound, accelerating the growth, and eventually leading to black hole formation. During the nonlinear growth phase, small scale features develop in the unstable mode and emitted radiation as nonlinear gravitational interactions mediate a direct turbulent cascade. The gravitational wave signal exhibits bursts, akin to so-called gravitational wave echoes, with increasing amplitude towards black hole formation.
format Preprint
id arxiv_https___arxiv_org_abs_2512_10526
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Nonlinear evolution of the ergoregion instability: Turbulence, bursts of radiation, and black hole formation
Siemonsen, Nils
East, William E.
General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
High Energy Physics - Theory
Spacetimes with an ergoregion that is not connected to a horizon are linearly unstable. While the linear regime has been studied in a number of settings, little is known about the nonlinear evolution of this ergoregion instability. Here, we investigate this by numerically evolving the unstable growth of a massless vector field in a rapidly spinning boson star in full general relativity. We find that the backreaction of the instability causes the star to become more gravitationally bound, accelerating the growth, and eventually leading to black hole formation. During the nonlinear growth phase, small scale features develop in the unstable mode and emitted radiation as nonlinear gravitational interactions mediate a direct turbulent cascade. The gravitational wave signal exhibits bursts, akin to so-called gravitational wave echoes, with increasing amplitude towards black hole formation.
title Nonlinear evolution of the ergoregion instability: Turbulence, bursts of radiation, and black hole formation
topic General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2512.10526