Probing interacting dark energy and scattering of baryons with dark matter in light of the EDGES 21-cm signal
Upala Mukhopadhyay, Debasish Majumdar, Kanan K. Datta
Abstract
The EDGES experiment has observed an excess trough ($\ensuremath{-}50{0}_{\ensuremath{-}500}^{+200}\text{ }\text{ }\mathrm{mK}$) in the brightness temperature ${T}_{21}$ of the 21-cm absorption line of neutral Hydrogen atom (HI) from the era of cosmic dawn ($z\ensuremath{\simeq}17.2$). We consider possible interaction of dark matter and dark energy fluid along with the cooling off of the baryon matter by its collision with dark matter to explain the observed excess trough of ${T}_{21}$. We make use of three different dark matter-dark energy (DM-DE) interaction models to test the viability of those models in explaining the EDGES results. The evolution of Hubble parameter is modified by DM-DE interactions and this is also addressed in this work. This in turn influences the optical depth of HI 21-cm as well as the baryon temperature and thus effects the ${T}_{21}$ brightness temperature. In addition we also find that the DM-DE interaction enables us to explore dark matter with varied mass regimes and their viabilities in terms of satisfying the EDGES result.