Constraints on primordial black holes and curvature perturbations from the global 21cm signal

Understand

The recent observations of the global 21cm signal by EDGES and gravitational waves by LIGO/VIGO have revived interest in PBHs.

• Different from previous works, we investigate the influence of PBHs on the evolution of the IGM for the mass range $6\times 10^{13} {\rm g} \lesssim M_{\rm PBH}\lesssim 3\times 10^{14} \rm g$.
• Since the lifetime of these PBHs is smaller than the present age of the Universe, they have evaporated by the present day.
• Due to Hawking radiation, the heating effects of PBHs on the IGM can suppress the absorption amplitude of the global 21cm signal.