Structure of Axion Miniclusters

Abstract

The Peak-Patch algorithm is used to identify the densest minicluster seeds in the initial axion density field simulated from string decay. The fate of these dense seeds is found by tracking the subsequent gravitational collapse in cosmological $N$-body simulations. We find that miniclusters at late times are well described by NFW profiles, although for around 80\% of simulated miniclusters a single power-law density profile of $r^{-2.9}$ is an equally good fit due to the unresolved scale radius. Under the assumption that all miniclusters with an unresolved scale radius are described by a power-law plus axion star density profile, we identify a significant number of miniclusters that might be dense enough to give rise to gravitational microlensing if the axion mass is $0.2\mathrm{meV}\lesssim m_a\lesssim 3\mathrm{meV}$. Higher resolution simulations resolving the inner structure and axion star formation are necessary to explore this possibility further.

10+8 pages, 15 figures, v2 further comments on density profile fits, matches version accepted in Phys Rev D

References in corpus (12)

• The NumPy array: a structure for efficient numerical computation
• Cosmic Structure as the Quantum Interference of a Coherent Dark Wave
• Measurement of the permanent electric dipole moment of the neutron
• Understanding the Core-Halo Relation of Quantum Wave Dark Matter, $\psi$DM, from 3D Simulations
• Non-thermal Dark Matter and the Moduli Problem in String Frameworks
• The dark-matter axion mass
• Axion cosmology with long-lived domain walls
• Improved estimation of radiated axions from cosmological axionic strings
• Astrophysical Effects of Scalar Dark Matter Miniclusters
• Small-scale clumps of dark matter
• Axion astronomy with microwave cavity experiments
• Destruction of axion miniclusters in the Galaxy

Cited by in corpus (23)

• Did JWST observe imprints of axion miniclusters or primordial black holes?
• Spectrum of global string networks and the axion dark matter mass
• Microlensing of gravitational waves by dark matter structures
• Soliton Formation and the Core-Halo Mass Relation: An Eigenstate Perspective
• Axion minivoids and implications for direct detection
• ALP Dark Matter Mini-Clusters from Kinetic Fragmentation
• Soliton Merger Rates and Enhanced Axion Dark Matter Decay
• Transient Radio Lines from Axion Miniclusters and Axion Stars
• Detecting Dark Matter Substructures on Small Scales with Fast Radio Bursts
• Post-inflationary axions: a minimal target for axion haloscopes
• Axion minicluster streams in the solar neighbourhood
• Enhanced Early Galaxy Formation in JWST from Axion Dark Matter?
• New Constraints on Dark Matter and Cosmic Neutrino Profiles through Gravity
• Axion star condensation around primordial black holes and microlensing limits
• Starlight from JWST: Implications for star formation and dark matter models
• On the Galactic radio signal from stimulated decay of axion dark matter
• Axions in Andromeda: Searching for Minicluster -- Neutron Star Encounters with the Green Bank Telescope
• High-redshift Galaxies from JWST Observations in More Realistic Dark Matter Halo Models
• Structure Formation with Warm White Noise: Effects of Finite Number Density and Velocity Dispersion in Particle and Wave Dark Matter
• Evidence for axion miniclusters with an increased central density
• Modified Cosmology or Modified Galaxy Astrophysics is Driving the z>6 JWST Results? CMB Experiments can discover the Origin in the Near Future
• Unified Gas Heating Constraints on Extended Dark Matter Compact Objects
• A self-consistent wave description of axion miniclusters and their survival in the galaxy