Indirect dark matter signatures in the cosmic dark ages. II. Ionization, heating, and photon production from arbitrary energy injections

By T. Slatyer. 2015

252 citations recorded by the source corpus.

Any injection of electromagnetically interacting particles during the cosmic dark ages will lead to increased ionization, heating, production of Lyman-alpha photons and distortions to the energy spectrum of the cosmic microwave background, with potentially observable consequences. In this note we describe numerical results for the low-energy electrons and photons produced by the cooling of particles injected at energies from keV to multi-TeV scales, at arbitrary injection redshifts (but focusing on the post-recombination epoch). We use these data, combined with existing calculations modeling the cooling of these low-energy particles, to estimate the resulting contributions to ionization, excitation and heating of the gas, and production of low-energy photons below the threshold for excitation and ionization. We compute corrected deposition-efficiency curves for annihilating dark matter, and demonstrate how to compute equivalent curves for arbitrary energy-injection histories. These calculations provide the necessary inputs for the limits on dark matter annihilation presented in the accompanying Paper I, but also have potential applications in the context of dark matter decay or de-excitation, decay of other metastable species, or similar energy injections from new physics. We make our full results publicly available at this http URL, to facilitate further independent studies. In particular, we provide the full low-energy electron and photon spectra, to allow matching onto more detailed codes that describe the cooling of such particles at low energies.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c387d3190fb756db23269175e1616ecb21ad07ef

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Citations in the corpus

INTEGRAL constraints on primordial black holes and particle dark matter (2020, background): “, in black), compared to the limits from CMB s- (purple solid) and p-wave (blue and green, dashed) [76].”
A Brief Review on Primordial Black Holes as Dark Matter (2021, background): “The energy deposition factors fc(z) quantify the fraction of energy which goes to the different channels, and has been computed numerically (Slatyer, 2016).”
Neutrino decoupling beyond the Standard Model: CMB constraints on the Dark Matter mass with a fast and precise Neff evaluation (2018, background): “This makes our bounds particularly relevant for p-wave annihilating relics to electrons since CMB observations are not sensitive to them [2, 62].”
Cosmological constraints on exotic injection of electromagnetic energy (2016, methodology): “Comparing now the results of the accurate treatment with the on-thespot approximate version, we find that the later works well for particles decaying with substantial energy deposition efficiency (here for 100 MeV), but not for high masses (100 GeV in the example of Fig.”
Production regimes for Self-Interacting Dark Matter (2015, background): “It is well known that light thermal DM annihilating via a s-wave into SM particles is strongly constrained by both CMB measurements and indirect DM searches at low redshifts [79, 80].”