Inner cusps of the first dark matter haloes: Formation and survival in a cosmological context

Abstract

We use very high resolution cosmological zoom simulations to follow the early evolution of twelve first-generation haloes formed from gaussian initial conditions with scale-free power spectra truncated on small scales by a gaussian in wavenumber. Initial collapse occurs with a diverse range of sheet- or filament-like caustic morphologies, but in almost all cases it gives rise to a numerically converged density cusp with $\rho =A{r}^{-3/2}$ and total mass comparable to that of the corresponding peak in the initial linear density field. The constant $A$ can be estimated to within about 10 per cent from the properties of this peak. This outcome agrees with earlier work on the first haloes in cold and warm dark matter universes. Within central cusps, the velocity dispersion is close to isotropic, and the equidensity surfaces tend to align with those of the main body of the halo at larger radii. As haloes grow, their cusps are often (but not always) overlaid with additional material at intermediate radii to produce profiles more similar to the Einasto or NFW forms typical of more massive haloes. Nevertheless, to the extent that we can resolve them, cusps survive at the smallest radii. Major mergers can disturb them, but the effect is quite weak in the cases that we study. The cusps extend down to the resolution limits of our simulations, which are typically a factor of several larger than the cores that would be produced by phase-space conservation if the initial power spectrum cutoff arises from free streaming.

24 pages, 29 figures; accepted by MNRAS. Includes further numerical convergence tests

References in corpus (11)

• Rotation-Dependent Catastrophic Disruption of Gravitational Aggregates
• Simulating cosmic structure formation with the GADGET-4 code
• Discreteness effects in simulations of Hot/Warm dark matter
• On Effective Degrees of Freedom in the Early Universe
• Hierarchical Formation of Dark Matter Halos and the Free Streaming Scale
• Joint constraints on thermal relic dark matter from strong gravitational lensing, the Lyman-$\alpha$ forest, and Milky Way satellites
• Probing Small-Scale Power Spectra with Pulsar Timing Arrays
• What sets the central structure of dark matter haloes?
• Fingerprints of the initial conditions on the density profiles of cold and warm dark matter haloes
• Phase-space structure of protohalos: Vlasov versus Particle-Mesh
• Prompt cusp formation from the gravitational collapse of peaks in the initial cosmological density field

Cited by in corpus (34)

• Gravitational wave lensing as a probe of halo properties and dark matter
• Prompt cusps and the dark matter annihilation signal
• Lensing constraints on ultradense dark matter halos
• Tidal evolution of cored and cuspy dark matter halos
• Structure formation with primordial black holes: collisional dynamics, binaries, and gravitational waves
• The effect of stellar encounters on the dark matter annihilation signal from prompt cusps
• Micro galaxies in LCDM
• On the effect of angular momentum on the prompt cusp formation via the gravitational collapse
• Massive prompt cusps: A new signature of warm dark matter
• Minihalos as probes of the inflationary spectrum: accurate boost factor calculation and new CMB constraints
• Limits on dark matter annihilation in prompt cusps from the isotropic gamma-ray background
• How an era of kination impacts substructure and the dark matter annihilation rate
• The Supersonic Project: The eccentricity and rotational support of SIGOs and DM GHOSts
• The Effects of Linear Matter Power Spectrum Enhancement on Dark Matter Substructure
• Toward More Realistic Mass Functions For Ultradense Dark Matter Halos
• Inner structure of dark matter halos at high $z$ in cosmological models with non-power-law primordial spectra
• 21-cm Constraints on Dark Matter Annihilation after an Early Matter-Dominated Era
• Can prompt cusps of WIMP dark matter be detected as individual gamma-ray sources?
• Gravitational Turbulence: the Small-Scale Limit of the Cold-Dark-Matter Power Spectrum
• Accurate halo mass functions from the simplest excursion set theory
• The gravitational force field of proto-pancakes
• Enhanced Small-Scale Structure in the Cosmic Dark Ages
• The cusp-halo relation
• Structure Formation with Warm White Noise: Effects of Finite Number Density and Velocity Dispersion in Particle and Wave Dark Matter
• Limits on Early Matter Domination from the Isotropic Gamma-Ray Background
• Constraints on dark matter models from the stellar cores observed in ultra-faint dwarf galaxies: Self-interacting dark matter
• New insights on low-mass dark matter subhalo tidal tracks via numerical simulations
• Can WIMPs Survive the Legacy of a Magnetised Early Universe?
• Dark matter halo dynamics in 2D Vlasov Simulations: a self-similar approach
• Excursion Sets with a "Perfect" Collapse Model
• Hints of Dark Matter Spikes in Low-mass X-ray Binaries: a critical assessment
• Prompt cusps in hierarchical dark matter halos: Implications for annihilation boost
• Post-collapse Lagrangian perturbation theory in three dimensions
• Role of prompt cusps in driving the core collapse of SIDM halos