Superdense cosmological dark matter clumps

Abstract

The formation and evolution of superdense clumps (or subhalos) is studied. Such clumps of dark matter (DM) can be produced by many mechanisms, most notably by spiky features in the spectrum of inflationary perturbations and by cosmological phase transitions. Being produced very early during the radiation dominated epoch, superdense clumps evolve as isolated objects. They do not belong to hierarchical structures for a long time after production, and therefore they are not destroyed by tidal interactions during the formation of larger structures. For DM particles with masses close to the electroweak (EW) mass scale, superdense clumps evolve towards a power-law density profile $\rho (r)\propto r^{-1.8}$ with a central core. Superdense clumps cannot be composed of standard neutralinos, since their annihilations would overproduce the diffuse gamma radiation. If the clumps are constituted of superheavy DM particles and develop a sufficiently large central density, the evolution of their central part can lead to a 'gravithermal catastrophe.' In such a case, the initial density profile turns into an isothermal profile with $\rho \propto r^{-2}$ and a new, much smaller core in the center. Superdense clumps can be bserved by gamma radiation from DM annihilations and by gravitational wave detectors, while the production of primordial black holes and cascade nucleosynthesis constrain this scenario.

9 pages, 6 eps figures; v2: 7 yr WMAP data included, to appear in PRD

References in corpus (31)

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• Dark Matter Substructure in Galactic Halos
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• Earth-mass dark-matter haloes as the first structures in the early Universe
• Density Profiles of Dark Matter Halo are not Universal
• The first WIMPy halos
• On the Origin of Cusps in Dark Matter Halos
• Probing Planckian physics: resonant production of particles during inflation and features in the primordial power spectrum
• Constraints on the density perturbation spectrum from primordial black holes
• Effects of cold dark matter decoupling and pair annihilation on cosmological perturbations
• Small-scale clumps in the galactic halo and dark matter annihilation
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Cited by in corpus (32)

• Probing the inflaton: Small-scale power spectrum constraints from measurements of the CMB energy spectrum
• Improved constraints on the primordial power spectrum at small scales from ultracompact minihalos
• Early Structure Formation in $\Lambda$PBH Cosmologies
• Reheating Effects in the Matter Power Spectrum and Implications for Substructure
• Testing scenarios of primordial black holes being the seeds of supermassive black holes by ultracompact minihalos and CMB $\mu$-distortions
• The Dark Matter Annihilation Boost from Low-Temperature Reheating
• Small-scale clumps of dark matter
• A new probe of the small-scale primordial power spectrum: astrometric microlensing by ultracompact minihalos
• Gamma-rays from ultracompact minihalos: potential constraints on the primordial curvature perturbation
• Formation and internal structure of superdense dark matter clumps and ultracompact minihaloes
• Gravitational wave lensing as a probe of halo properties and dark matter
• Physical laboratory at the center of the Galaxy
• Number Counts and Non-Gaussianity
• Astrometric Microlensing by Local Dark Matter Subhalos
• Lensing constraints on ultradense dark matter halos
• Cannibalism's lingering imprint on the matter power spectrum
• Hunting for dark halo substructure using submilliarcsecond-scale observations of macrolensed radio jets
• Dark Matter Decay and the Abundance of Ultracompact Minihalos
• Annihilations of superheavy dark matter in superdense clumps
• New Class of Dark Matter Objects and their Detection
• Constraints on cosmic strings from ultracompact minihalos
• Boosting small-scale structure via primordial black holes and implications for sub-GeV dark matter annihilation
• A new bound on the low reheating temperature with dark matter
• Dark Matter Signatures of Supermassive Black Hole Binaries
• Flaring of tidally compressed dark-matter clumps
• How an era of kination impacts substructure and the dark matter annihilation rate
• Radio bounds on the mixed dark matter scenarios of primordial black holes and WIMPs
• Enhanced spectrum of primordial perturbations, galaxy formation and small scale structure
• Ultradense Dark Matter Halos with Poisson Noise from Stellar-Mass Primordial Black Holes
• SUSY dark matter annihilation in the Galactic halo
• Assisted baryon number violation from $4k+2$ dimensions
• Probing Dark Matter Clumps, Strings and Domain Walls with Gravitational Wave Detectors