Known Unknowns of Dark Matter Annihilation over Cosmic Time

Abstract

Dark matter self-annihilation holds promise as one of the most robust mechanisms for the identification of the particle responsible for the Universe's missing mass. In this work, I examine the evolution of the dark matter annihilation power produced by smooth and collapsed structures over cosmic time, taking into account uncertainties in the structure of dark matter halos. As we search for observational signatures of annihilation, an understanding of this time evolution will help us to best direct our observational efforts, either with local measurements or investigation of the effects of annihilation on the intergalactic medium at high redshift. As I show in this work, there are several key sources of uncertainty in our ability to estimate the dark matter annihilation from collapsed structures, including: the density profile of dark matter halos; the small-scale cut-off in the dark matter halo mass function; the redshift-dependent mass-concentration relation for small halos; and the particle-velocity dependence of the dark matter annihilation process. Varying assumptions about these quantities can result in annihilation power predictions that differ by several orders of magnitude. These uncertainties must be resolved, through a combination of observation and modeling, before robust estimations of the cosmological annihilation signal can be made.

9 pages, 7 figures. This version accepted for publication in MNRAS. Contains new halo models and concentration relations, some clarification of discussion, additional references, and additional acknowledgments

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Cited by in corpus (19)

• The accretion history of dark matter halos III: A physical model for the concentration-mass relation
• Limits on Dark Matter Annihilation Signals from the Fermi LAT 4-year Measurement of the Isotropic Gamma-Ray Background
• The Darkest Hour Before Dawn: Contributions to Cosmic Reionization from Dark Matter Annihilation and Decay
• The nature of the Diffuse Gamma-Ray Background
• Hierarchical Formation of Dark Matter Halos and the Free Streaming Scale
• Dark matter substructure modelling and sensitivity of the Cherenkov Telescope Array to Galactic dark halos
• Dark-ages Reionization & Galaxy Formation Simulation I: The dynamical lives of high redshift galaxies
• Dark-ages Reionization & Galaxy Formation Simulation II: Spin and concentration parameters for dark matter haloes during the Epoch of Reionization
• Extragalactic diffuse gamma-rays from dark matter annihilation: revised prediction and full modelling uncertainties
• Enhanced n-body annihilation of dark matter and its indirect signatures
• Heating of galactic gas by dark matter annihilation in ultracompact minihalos
• Dark Matter Annihilation in the Circumgalactic Medium at High Redshifts
• Imprints of decaying dark matter on cosmic voids
• Self-Interacting Dark Matter Scattering Rates Through Cosmic Time
• Dark Matter Annihilation Feedback in cosmological simulations I: Code convergence and idealised halos
• Cosmological boost factor for dark matter annihilation at redshifts of $z=10$-$100$ using the power spectrum approach
• The Effects of Dark Matter Annihilation and Dark Matter-Baryon Velocity Offsets at Cosmic Dawn
• Dark Matter Energy Deposition and Production from the Table-Top to the Cosmos
• Dark Matter Annihilation in the First Galaxy Halos