Signatures of inhomogeneous dark matter annihilation on 21-cm

Abstract

The energy released from dark matter (DM) annihilation leads to additional ionization and heating of the intergalactic gas, impacting the hydrogen 21-cm signal during the cosmic dawn. The dark matter annihilation rate scales with its density squared and becomes inhomogeneously boosted with structure formation. This paper examines the inhomogeneity in DM annihilation rate induced by the growth of DM halo structures, and we show that this effect can significantly amplify the spatial fluctuations in temperature and ionization fraction of the gas. Consequently, the fluctuations in the 21-cm brightness temperature may also be enhanced. We showcase these effects for a DM mass of 100 MeV annihilating into ${\mathrm{e}}^{-}{\mathrm{e}}^{+}$ at a rate of $⟨\sigma v⟩/m_{\chi }\sim 10^{-27}\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}\mathrm{Ge}{\mathrm{V}}^{-1}$, which is consistent with current constraints set by the cosmic microwave background. We find that, compared to the homogeneous calculations, inhomogeneous annihilation can enhance the 21-cm power spectrum by up to a factor of 130 over the scales of $k\in [0.05,3]\mathrm{Mp}{\mathrm{c}}^{-1}$ at redshifts $11-16$. Such signatures could potentially be detected by upcoming radio observatories such as the Square Kilometer Array telescope.

arXiv commentPRD accepted version, added ORCID for the third author compared to the published version. 12 pages, 5 figures

References in corpus (55)

• A Universal Density Profile from Hierarchical Clustering
• Large scale bias and the peak background split
• Halo Models of Large Scale Structure
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• In the Beginning: The First Sources of Light and the Reionization of the Universe
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• 21-cm cosmology
• An excursion set model of hierarchical clustering: Ellipsoidal collapse and the moving barrier
• 21cmFAST: A Fast, Semi-Numerical Simulation of the High-Redshift 21-cm Signal
• Concentration, Spin and Shape of Dark Matter Haloes as a Function of the Cosmological Model: WMAP1, WMAP3 and WMAP5 results
• A New Calculation of the Recombination Epoch
• Concentration, Spin and Shape of Dark Matter Haloes: Scatter and the Dependence on Mass and Environment
• Model-independent evidence in favor of an end to reionization by z~6
• Indirect Dark Matter Signatures in the Cosmic Dark Ages I. Generalizing the Bound on s-wave Dark Matter Annihilation from Planck
• CMB Constraints on WIMP Annihilation: Energy Absorption During the Recombination Epoch
• Reionization after Planck: The Derived Growth of the Cosmic Ionizing Emissivity now matches the Growth of the Galaxy UV Luminosity Density
• The Dearth of z~10 Galaxies in all HST Legacy Fields -- The Rapid Evolution of the Galaxy Population in the First 500 Myr
• How to Plant a Merger Tree
• Detecting Dark Matter Annihilation with CMB Polarization : Signatures and Experimental Prospects
• Limits to dark matter annihilation cross-section from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies
• Damping scales of neutralino cold dark matter
• General Constraints on Dark Matter Decay from the Cosmic Microwave Background
• Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal
• HyRec: A fast and highly accurate primordial hydrogen and helium recombination code
• New limits on dark matter annihilation from AMS cosmic ray positron data
• Particle Models and the Small-Scale Structure of Dark Matter
• Indirect Dark Matter Signatures in the Cosmic Dark Ages II. Ionization, Heating and Photon Production from Arbitrary Energy Injections
• What mass are the smallest protohalos?
• The flattening of the concentration-mass relation towards low halo masses and its implications for the annihilation signal boost
• Overcoming real-world obstacles in 21 cm power spectrum estimation: A method demonstration and results from early Murchison Widefield Array data
• Opening the 21cm EoR Window: Measurements of Foreground Isolation with PAPER
• Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array
• The Cosmic Dawn and Epoch of Reionization with the Square Kilometre Array
• The Darkest Hour Before Dawn: Contributions to Cosmic Reionization from Dark Matter Annihilation and Decay
• Energy Injection And Absorption In The Cosmic Dark Ages
• The Clumpiness of Cold Dark Matter: Implications for the Annihilation Signal
• The Imprint of Warm Dark Matter on the Cosmological 21-cm Signal
• AMS-02 antiprotons, at last! Secondary astrophysical component and immediate implications for Dark Matter
• Constraints on dark matter annihilation from CMB observations before Planck
• Constraining dark matter late-time energy injection: decays and p-wave annihilations
• Reionization and Beyond: detecting the peaks of the cosmological 21cm signal
• Constraints on leptonically annihilating Dark Matter from reionization and extragalactic gamma background
• DarkHistory: A code package for calculating modified cosmic ionization and thermal histories with dark matter and other exotic energy injections
• The Epoch of Helium Reionization
• Thermal decoupling and the smallest subhalo mass in dark matter models with Sommerfeld-enhanced annihilation rates
• The nature of dark matter from the global high redshift HI 21 cm signal
• The 21 cm signal and the interplay between dark matter annihilations and astrophysical processes
• HYREC-2: a highly accurate sub-millisecond recombination code
• 21-cm constraints on spinning primordial black holes
• Les Houches Lectures on Indirect Detection of Dark Matter
• Cosmic radiation backgrounds from primordial black holes
• Powerbox: A Python package for creating structured fields with isotropic power spectra
• Distinguishing standard reionization from dark matter models
• 21cm signal sensitivity to dark matter decay
• Enlightening the dark ages with dark matter