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

Understand

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.