Extreme $\ell$-boson stars

Abstract

A new class of complex scalar field objects, which generalize the well known boson stars, was recently found as solutions to the Einstein-Klein-Gordon system. The generalization consists in incorporating some of the effects of angular momentum, while still maintaining the spacetime's spherical symmetry. These new solutions depend on an (integer) angular parameter $\ell$, and hence were named $\ell$-boson stars. Like the standard $\ell =0$ boson stars these configurations admit a stable branch in the solution space; however, contrary to them they have a morphology that presents a shell-like structure with a "hole" in the internal region. In this article we perform a thorough exploration of the parameter space, concentrating particularly on the extreme cases with large values of $\ell$. We show that the shells grow in size with the angular parameter, doing so linearly for large values, with the size growing faster than the thickness. Their mass also increases with $\ell$, but in such a way that their compactness, while also growing monotonically, converges to a finite value corresponding to about one half of the Buchdahl limit for stable configurations. Furthermore, we show that $\ell$-boson stars can be highly anisotropic, with the radial pressure diminishing relative to the tangential pressure for large $\ell$, reducing asymptotically to zero, and with the maximum density also approaching zero. We show that these properties can be understood by analyzing the asymptotic limit $\ell \to \infty$ of the field equations and their solutions. We also analyze the existence and characteristics of both timelike and null circular orbits, especially for very compact solutions.

arXiv comment22 pages. To appear in Classical and Quantum Gravity - (Focus Issue on Bosonic Stars)

References in corpus (40)

• Axion Cosmology
• Cold and Fuzzy Dark Matter
• Ultralight scalars as cosmological dark matter
• Cosmic Structure as the Quantum Interference of a Coherent Dark Wave
• Testing the nature of dark compact objects: a status report
• Understanding the Core-Halo Relation of Quantum Wave Dark Matter, $\psi$DM, from 3D Simulations
• Late time Cosmological Phase Transition and Galactic Halo as Bose-liquid
• Light ring stability in ultra-compact objects
• Simulations of solitonic core mergers in ultra-light axion dark matter cosmologies
• A Further Analysis of a Cosmological Model of Quintessence and Scalar Dark Matter
• Galactic Halos As Boson Stars
• There is No Missing Satellites Problem
• GW190521 as a merger of Proca stars: a potential new vector boson of $8.7\times 10^{-13}$ eV
• Spectral Methods for Numerical Relativity
• A new cosmological tracker solution for Quintessence
• Galactic Halos of Fluid Dark Matter
• Gravitational Wave Signatures of Highly Compact Boson Star Binaries
• Scalar Field as Dark Matter in the Universe
• Dynamical Evolution of Boson Stars II: Excited States and Self-Interacting Fields
• Boson Stars and Oscillatons: A Review
• Multi-state Boson Stars
• On the final fate of compact boson star mergers
• Cosmological particle-in-cell simulations with ultralight axion dark matter
• Models of rotating boson stars and geodesics around them: new type of orbits
• The core-cusp problem: a matter of perspective
• Scalar Field Dark Matter: Helping or Hurting Small-Scale Problems in Cosmology?
• $\ell$-Boson stars
• Narrowing the mass range of Fuzzy Dark Matter with Ultra-faint Dwarfs
• Gravitational Waves from Dark Boson Star binary mergers
• On the steady states of the spherically symmetric Einstein-Vlasov system
• On static shells and the Buchdahl inequality for the spherically symmetric Einstein-Vlasov system
• Multi-field, multi-frequency bosonic stars and a stabilization mechanism
• Light rings and long-lived modes in quasi-black hole spacetimes
• Dynamical evolutions of $\ell$-boson stars in spherical symmetry
• Dynamical $\ell$-boson stars: generic stability and evidence for non-spherical solutions
• Critical Behavior in the Gravitational Collapse of a Scalar Field with Angular Momentum in Spherical Symmetry
• The Core-Cusp Problem Revisited: ULDM vs. CDM
• Horndeski stars
• On the linear stability of $\ell$-boson stars with respect to radial perturbations
• Scalar field confinement as a model for accreting systems

Cited by in corpus (17)

• Dynamical Boson Stars
• Head-on collisions of $\ell$-boson stars
• Unequal-mass boson-star binaries: Initial data and merger dynamics
• Boson stars and their relatives in semiclassical gravity
• A Sun-like star orbiting a boson star
• On the radial linear stability of nonrelativistic $\ell$-boson stars
• Nonradial instabilities in anisotropic neutron stars
• Are nonrelativistic ground state $\ell$-boson stars only stable for $\ell =0$ and $\ell =1$?
• Total light bending in non-asymptotically flat black hole spacetimes
• Boson star superradiance with spinning effects and in time domain
• Magnetostatic boson stars
• Born-Infeld boson stars
• Confinement of exotic matter. I. Static solutions
• Noble gravitational atoms: Self-gravitating black hole scalar wigs with angular momentum number
• Slowly Rotating Boson Stars
• $\ell$-Boson stars in anti-de Sitter spacetime
• Intrinsic pressure anisotropy in spherical Proca stars