| dc.description.abstract | While gravitational effects of dark matter are observed at galactic and larger scales, other behaviors are more elusive. Two approaches for extra-solar studies of dark matter interaction are from an energy perspective and through spectral searches. Energy injections into the intergalactic medium over the age of the Universe from exotic interactions, including dark matter, result in a perturbed gas evolution which has measurable impacts on both the cosmic microwave background (CMB) as well as the 21 cm absorption line. Sizable particle spectra are also produced in areas of dense matter concentrations. This work studies the effects of energy injections and spectral signals in the context of dark matter, and limits are placed on multiple models using results from Planck, Fermi-LAT, MAGIC, VERITAS, AMS, and EDGES. Decaying dark matter is well constrained by 21 cm absorption, especially for 2e and 2γ modes and most models with dark matter lighter than 20 GeV. Primordial black hole evaporation strongly affects both the CMB and the 21 cm line; while the limits from CMB measurements are comparable to current leading bounds, those from 21 cm absorption are an order of magnitude stronger.
In four-body annihilation models, spectral signals weaken slightly while the CMB remains mostly unchanged. Gauge boson bremsstrahlung annihilation improves the reach of velocity suppressed model searches with spectral signals from the galactic center proving the most stringent. | en |
