Title: Dark Matter Annihilation in the Circumgalactic Medium at High Redshifts,
Abstract: Annihilating dark matter (DM) models offer promising avenues for future DM
detection, in particular via modification of astrophysical signals. However
when modelling such potential signals at high redshift the emergence of both
dark matter and baryonic structure, as well as the complexities of the energy
transfer process, need to be taken into account. In the following paper we
present a detailed energy deposition code and use this to examine the energy
transfer efficiency of annihilating dark matter at high redshift, including the
effects on baryonic structure. We employ the PYTHIA code to model
neutralino-like DM candidates and their subsequent annihilation products for a
range of masses and annihilation channels. We also compare different density
profiles and mass-concentration relations for 10^5-10^7 M_sun haloes at
redshifts 20 and 40. For these DM halo and particle models, we show radially
dependent ionisation and heating curves and compare the deposited energy to the
haloes' gravitational binding energy. We use the "filtered" annihilation
spectra escaping the halo to calculate the heating of the circumgalactic medium
and show that the mass of the minimal star forming object is increased by a
factor of 2-3 at redshift 20 and 4-5 at redshift 40 for some DM models.