The impact of EDGES 21-cm data on dark matter interactions

TL;DR

The paper demonstrates that EDGES 21-cm data significantly constrains dark matter annihilation properties by accurately modeling heating effects, surpassing previous limits from Planck in certain mass ranges.

Contribution

It introduces a detailed radiative transfer model accounting for dark matter heating, providing new, tighter constraints on dark matter annihilation cross-sections from 21-cm observations.

Findings

EDGES data yields more stringent limits than Planck for low-mass dark matter.

Proper modeling of heating effects is crucial for accurate constraints.

21-cm absorption profiles are effective probes of dark matter interactions.

Abstract

The recently announced results on the 21-cm absorption spectrum by the EDGES experiment can place very stringent limits on dark matter annihilation cross-sections. We properly take into account the heating energy released from dark matter annihilation from the radiation epoch to the 21-cm observation redshifts in the radiative transfer to compute the evolution of the gas temperature. Our results show that the global 21-cm absorption profile is a powerful cosmological probe of the dark matter interactions. For dark matter annihilating into electron-positron pairs, the EDGES results give a more stringent upper limit than the PLANCK result on the annihilation cross section at the lower dark matter mass region.