@article{fd81bc79d15a409488b243d24259d686,
title = "Electromagnetic instability of compact axion stars",
abstract = "If the dark matter is composed of axions, then axion stars are expected to be abundant in the Universe. We demonstrate in fully nonlinear (3+1) numerical relativity the instability of compact axion stars due to the electromagnetic Chern-Simons term. We show that above the critical coupling constant gaγcrit∝Ms-1.35, compact axion stars of mass Ms are unstable. The instability is caused by parametric resonance between the axion and the electromagnetic field. The existence of stable compact axion stars requires approximately Planck-suppressed couplings to photons. If the coupling exceeds the critical value, then all stable axion stars are necessarily noncompact. Unstable axion stars decay leaving behind a less massive, less compact, remnant. The emitted radiation peaks at a frequency ω∼1/Rs, where Rs is the axion star radius.",
author = "Chung-Jukko, {Liina M.} and Lim, {Eugene A.} and Marsh, {David J.E.} and Aurrekoetxea, {Josu C.} and {De Jong}, Eloy and Ge, {Bo Xuan}",
note = "Funding Information: We would like to thank Thomas Helfer for his early contribution to the project. We also thank members of the grchombo Collaboration for technical support and help. L. M. C. J. is supported by a studentship funded by the Science and Technologies Facilities Council (U.K.). D. J. E. M. is supported by an Ernest Rutherford Fellowship from the Science and Technologies Facilities Council (No. ST/T004037/1). J. C. A. acknowledges funding from the Beecroft Trust and The Queen{\textquoteright}s College via an extraordinary Junior Research Fellowship (eJRF). This work used the DiRAC@Durham Cosma facility managed by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk), under DiRAC Grant No. ACTP238. The equipment was funded by BEIS capital funding via STFC Capital Grants No. ST/P002293/1, No. ST/R002371/1, and No. ST/S002502/1, Durham University and STFC Operations Grant No. ST/R000832/1. Publisher Copyright: {\textcopyright} 2023 authors. Published by the American Physical Society.",
year = "2023",
month = sep,
day = "15",
doi = "10.1103/PhysRevD.108.L061302",
language = "English",
volume = "108",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "American Physical Society (APS)",
number = "6",
}