The contribution of ultracompact dark matter minihalos to the isotropic radio background

Abstract

The ultracompact minihalos could be formed during the earlier epoch of the universe. The dark matter annihilation within them is very strong due to the steep density profile, $\rho \sim r^{-2.25}$. The high energy electrons and positrons from the dark matter annihilation can inverse Compton scatter (ICS) with the background photons, such as CMB photons, to acquire higher energy. On the other hand, the synchrotron radiation can also be produced when they meet the magnetic field. In this paper, we study the signals from the UCMHs due to the dark matter annihilation for the radio, X-ray and $\gamma$-ray band. We found that for the radio emission the UCMHs can provide one kind of source for the radio excess observed by ARCADE 2. But the X-ray signals due to the ICS effect or the $\gamma$-ray signals mainly due to the prompt emission from dark matter would exceed the present observations, such as Fermi, COMPTEL and CHANDRA. We found that the strongest limits on the fraction of UCMHs come from the X-ray observations and the constraints from the radio data are the weakest.

6 pages, 8 figures, Comments Welcome! Some Refs. are added, some presentation have been corrected. The conclusions remain unchanged. One important reference has been corrected. Some presentations are changed and added according to the referee's comments. Accepted for publication in PRD

References in corpus (15)

• A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
• The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
• Improved constraints on the primordial power spectrum at small scales from ultracompact minihalos
• Detecting dark matter WIMPs in the Draco dwarf: a multi-wavelength perspective
• All-sky Galactic radiation at 45 MHz and spectral index between 45 and 408 MHz
• Single-field inflation, anomalous enhancement of superhorizon fluctuations, and non-Gaussianity in primordial black hole formation
• The contribution of the Unresolved Extragalactic Radio Sources to the Brightness Temperature of the sky
• A dark matter interpretation for the ARCADE excess?
• Gamma-rays from ultracompact minihalos: potential constraints on the primordial curvature perturbation
• Extragalactic Inverse Compton Light from Dark Matter Annihilation and the Pamela Positron Excess
• The Isotropic Radio Background and Annihilating Dark Matter
• Constraints on ultracompact minihalos from extragalactic γ-ray background
• Cosmological Radio Emission induced by WIMP Dark Matter
• New Constraints on Primordial Minihalo Abundance Using Cosmic Microwave Background Observations
• The Abundance of New Kind of Dark Matter Structures

Cited by in corpus (19)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Testing scenarios of primordial black holes being the seeds of supermassive black holes by ultracompact minihalos and CMB $\mu$-distortions
• Constraints on dark matter annihilation from CMB observations before Planck
• Density profiles of ultracompact minihalos: Implications for constraining the primordial power spectrum
• Are ultracompact minihalos really ultracompact?
• Small-scale clumps of dark matter
• Investigating dark matter substructure with pulsar timing: I. Constraints on ultracompact minihalos
• 3D simulations with boosted primordial power spectra and ultracompact minihalos
• The Radio Synchrotron Background: Conference Summary and Report
• The isotropic radio background revisited
• The Deep Diffuse Extragalactic Radio Sky at 1.75 GHz
• The Second Radio Synchrotron Background Workshop: Conference Summary and Report
• Contributions of dark matter annihilation to the global 21cm spectrum observed by the EDGES experiment
• Investigating dark matter substructure with pulsar timing: II. Improved limits on small-scale cosmology
• Cosmic ray $e^{+}{e}^{-}$ spectrum excess and peak feature observed by the DAMPE experiment from dark matter
• Constraints on cosmic strings from ultracompact minihalos
• Constraints on the ultracompact minihalos using neutrino signals from the gravitino dark matter decay
• Semi-analytical frameworks for subhalos from the smallest to the largest scale
• The Excess Radio Background and Fast Radio Transients