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

Abstract

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 Dark Matter - baryon interaction and primordial black holes (PBH) in the 21cm brightness temperature signal. The variation of brightness temperature shows remarkable dependence on dark matter mass ($m_{\\chi}$) and the dark matter - baryon cross-section ($\\overline{\\sigma}_0$) besides the PBH parameters (mass $\\mathcal{M_{\\rm BH}}$ and initial mass fraction $\\beta_{\\rm BH}$). We describe both upper and lower bounds on $\\beta_{\\rm BH}$ for a wide range of PBH mass for different chosen parameters of Dark Matter - baryon interaction using 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 values of black hole masses.