Stability of rotating scalar boson stars with nonlinear interactions

Abstract

We study the stability of rotating scalar boson stars, comparing those made from a simple massive complex scalar (referred to as mini boson stars), to those with several different types of nonlinear interactions. To that end, we numerically evolve the nonlinear Einstein-Klein-Gordon equations in 3D, beginning with stationary boson star solutions. We show that the linear, non-axisymmetric instability found in mini boson stars with azimuthal number $m=1$ persists across the entire parameter space for these stars, though the timescale diverges in the Newtonian limit. Therefore, any boson star with $m=1$ that is sufficiently far into the non-relativistic regime, where the leading order mass term dominates, will be unstable, independent of the nonlinear scalar self-interactions. However, we do find regions of $m=1$ boson star parameter space where adding nonlinear interactions to the scalar potential quenches the non-axisymmetric instability, both on the non-relativistic, and the relativistic branches of solutions. We also consider select boson stars with $m=2$, finding instability in all cases. For the cases exhibiting instability, we follow the nonlinear development, finding a range of dynamics including fragmentation into multiple unbound non-rotating stars, and formation of binary black holes. Finally, we comment on the relationship between stability and criteria based on the rotating boson star's frequency in relation to that of a spherical boson star or the existence of a co-rotation point. The boson stars that we find not to exhibit instability when evolved for many dynamical times include rapidly rotating cases where the compactness is comparable to that of a black hole or neutron star.

16 pages, 11 figures; revised to match PRD version

References in corpus (16)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Ultralight scalars as cosmological dark matter
• Compact stars made of fermionic dark matter
• Black Holes as Effective Geometries
• Gravitational Wave Signatures of Highly Compact Boson Star Binaries
• Head-on collisions of boson stars
• Gravitational Stability of Boson Stars
• Orbital Dynamics of Binary Boson Star Systems
• Rotating Boson Stars and Q-Balls II: Negative Parity and Ergoregions
• The response of ultralight dark matter to supermassive black holes and binaries
• Dark compact objects: an extensive overview
• An Improved Gauge Driver for the Generalized Harmonic Einstein System
• Spherical Boson Stars as Black Hole mimickers
• Excited Boson Stars
• How does gravity save or kill Q-balls?
• Black Holes, Black Rings and their Microstates

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