Explaining the results of EDGES observation of 21cm line with Dark Matter-Dark Energy and Dark Matter-Baryon interactions

Abstract

The EDGES experiment related to the observant of brightness temperature \(T_{21}\) of 21cm line arising from ground state of neutral Hydrogen atom, has shown an excess absorption feature ( \(− 500^ {+200}_{ − 500}\) mK) in \(T_{21}\) spectrum corresponds to the era of cosmic dawn (\(z \sim 17.2\)). In order to explain the observed excess trough of \(T_{21}\) we consider Interacting Dark Energy scenario (interaction of Dark Matter and Dark Energy) along with the scattering of baryon matter with Dark Matter. Three different Interacting Dark Energy (IDE) models are used and the viability of those models are tested in the context of EDGES experimental results. It is found that Dark Matter-Dark Energy interaction modifies the evolution process of the Universe and hence consequently affects the brightness temperature. Dark Matter-baryon interaction also affects the \(T_{21}\) temperature since baryon fluid would transfer heat to the colder Dark Matter due to the Dark Matter baryon collision. In addition we also give bounds on the model parameters of the IDE models and Dark Matter model from EDGES observational data. It is noted that Dark Matter-Dark Energy interaction enables to explore larger range of Dark Matter mass regimes that would satisfy the EDGES result.

Keywords

• Dark Energy
• Dark Matter
• 21 cm line of Hydrogen atom