Constraint on the abundance of primordial black holes in dark matter from Planck data

Abstract

We use Planck data released in 2015 to constrain the abundance of primordial black holes (PBHs) in dark matter in two different reionization models (one is the instantaneous reionization and the other is the asymmetric reionization), and significantly improve the existing upper limits on the abundance of PBHs by around two orders of magnitude. These new limits imply that the event rates of mergers of PBH binaries (Gpc^-3 yr^-1) are less than 0.002 for M_pbh = 30M_solar, 5 for M_pbh = 10M_solar and 2000 for M_pbh = 2M_solar at 95% confidence level (C.L.), and thus the gravitational-wave event GW150914 is very unlikely produced by the merger of a PBH binary.