Angular Momentum and the Absence of Vortices in the Cores of Fuzzy Dark Matter Haloes

Abstract

Scalar Field Dark Matter (SFDM), comprised of ultralight ($\gtrsim 10^{-22}$ eV) bosons, is distinguished from massive ($\gtrsim$ GeV), collisionless Cold Dark Matter (CDM) by its novel structure-formation dynamics as Bose-Einstein condensate (BEC) and quantum superfluid with wave-like properties, described by the Gross-Pitaevski and Poisson (GPP) equations. In the free-field (fuzzy) limit of SFDM (FDM), structure is inhibited below the de Broglie wavelength ${\lambda }_{\text{deB}}$, but resembles CDM on larger scales. Virialized haloes have solitonic cores of radius $\sim {\lambda }_{\text{deB}}$ that follow the ground-state attractor solution of GPP, surrounded by CDM-like envelopes. As superfluid, SFDM is irrotational (vorticity-free) but can be unstable to vortex formation. We previously showed this can happen in halo cores, from angular momentum arising during structure formation, when repulsive self-interaction (SI) is present to support them out to a second length scale ${\lambda }_{\text{SI}}$ with ${\lambda }_{\text{SI}}>{\lambda }_{\text{deB}}$ (the Thomas-Fermi regime), but only if SI is strong enough. This suggested FDM cores (without SI) would not form vortices. FDM simulations later found vortices, but only outside halo cores, consistent with our previous suggestion based upon TF-regime analysis. We extend that analysis now to FDM, to show explicitly that vortices should not arise in solitonic cores from angular momentum, modelling them as either Gaussian spheres or compressible, ($n=2$)-polytropic, irrotational Riemann-S ellipsoids. We find that, for typical halo spin parameters, angular momentum per particle is below $\hslash$, the minimum required even for one singly-quantized vortex in the centre. Even for larger angular momentum, however, vortex formation is not energetically favoured.

arXiv commentaccepted by MNRAS, 29 pages, 9 figures; minor revisions

References in corpus (32)

• String Axiverse
• Cold and Fuzzy Dark Matter
• Ultralight scalars as cosmological dark matter
• Axions In String Theory
• Small-Scale Challenges to the $\Lambda$CDM Paradigm
• Cosmic Structure as the Quantum Interference of a Coherent Dark Wave
• A universal angular momentum profile for galactic halos
• Cosmology with Ultra-light Pseudo-Nambu-Goldstone Bosons
• Ground-State Properties of Magnetically Trapped Bose-Condensed Rubidium Gas
• Understanding the Core-Halo Relation of Quantum Wave Dark Matter, $\psi$DM, from 3D Simulations
• Mass-radius relation of Newtonian self-gravitating Bose-Einstein condensates with short-range interactions: I. Analytical results
• Cold dark matter: controversies on small scales
• Formation of Solitonic Stars Through Gravitational Cooling
• Galaxy Formation with BECDM: I. Turbulence and relaxation of idealised haloes
• Simulations of solitonic core mergers in ultra-light axion dark matter cosmologies
• The distribution of dark matter in galaxies
• Axion dark matter, solitons, and the cusp-core problem
• Evolution of the Schrödinger--Newton system for a self--gravitating scalar field
• Angular Momentum and Vortex Formation in Bose-Einstein-Condensed Cold Dark Matter Haloes
• Analysis of Dark Matter Axion Clumps with Spherical Symmetry
• Complex scalar field dark matter on galactic scales
• PyUltraLight: A Pseudo-Spectral Solver for Ultralight Dark Matter Dynamics
• Gravitational excitons from extra dimensions
• Vortices and waves in light dark matter
• Derivation of the core mass -- halo mass relation of fermionic and bosonic dark matter halos from an effective thermodynamical model
• Core-Halo Mass Relation in Scalar Field Dark Matter Models and its Consequences for the Formation of Supermassive Black Holes
• Vortex Structures in a Rotating BEC Dark Matter Component
• Head-on collision of multi-state ultralight BEC dark matter configurations
• Dissecting the spin distribution of Dark Matter halos
• Gravitational Stability of Vortices in Bose-Einstein Condensate Dark Matter
• Vortices and Angular Momentum in Bose-Einstein-Condensed Cold Dark Matter Halos
• Ultralight Repulsive Dark Matter and BEC

Cited by in corpus (12)

• Coherent and incoherent structures in fuzzy dark matter halos
• Intergalactic filaments spin
• Cosmic Filament Spin from Dark Matter Vortices
• Gravitational Stability of Vortices in Bose-Einstein Condensate Dark Matter
• Scalar dark matter vortex stabilization with black holes
• Single and merger soliton dynamics in scalar field dark matter with and without self-interactions
• Construction and evolution of equilibrium configurations of the Schrödinger-Poisson system in the Madelung frame
• Solving the Schrodinger Poisson System using the coordinate Adaptive Moving Mesh method
• Kinematic Imprints of vortex-lines of BEC Dark Matter on Baryonic Matter
• 3D Vortices and rotating solitons in ultralight dark matter
• Constraining Axion Dark Matter with Galactic-Centre Resonant Dynamics
• To observe, or not to observe, quantum-coherent dark matter in the Milky Way, that is a question