Bounds on abundance of primordial black hole and dark matter from EDGES 21-cm signal

Abstract

The redshifted 21cm radio signal has emerged as an important probe for investigating the dynamics of the dark age Universe (recombination to reionization). In the current analysis, we explore the combined effect of primordial black hole (PBH) evaporation and the baryon-dark matter (DM) interaction in the 21cm scenario. The variation of brightness temperature shows remarkable dependence on the DM masses ($m_{\chi}$) and the baryon-DM cross-sections ($\overline{\sigma}_0$) besides the influences of the PBH parameters (mass $\mathcal{M_{\rm BH}}$ and initial mass fraction $\beta_{\rm BH}$). We address both upper and lower bounds on $\beta_{\rm BH}$ for a wide range of PBH mass in presence of different $m_{\chi}$ and $\overline{\sigma}_0$ by incorporating the observational excess $\left(-500^{+200}_{-500}\: {\rm mK}\right)$ of EDGES's experimental results. Finally, we address similar limits in the $m_{\chi}$ - $\overline{\sigma}_0$ parameter plane for different PBH masses.