Constraints on the Primordial Black Hole Abundance from the First Advanced LIGO Observation Run Using the Stochastic Gravitational-Wave Background

Abstract

Advanced LIGO's discovery of gravitational-wave events is stimulating extensive studies on the origin of binary black holes. Assuming that the gravitational-wave events can be explained by binary primordial black hole mergers, we utilize the upper limits on the stochastic gravitational-wave background given by Advanced LIGO as a new observational window to independently constrain the abundance of primordial black holes in dark matter. We show that Advanced LIGO's first observation run gives the best constraint on the primordial black hole abundance in the mass range $1 M_\odot \lesssim M_\text{PBH}\lesssim 100 M_\odot$, pushing the previous microlensing and dwarf galaxy dynamics constraints tighter by 1 order of magnitude. Moreover, we discuss the possibility to detect the stochastic gravitational-wave background from primordial black holes, in particular from subsolar mass primordial black holes, by Advanced LIGO in the near future.

Figures (2)

• Figure 1: The constraints on the PBH fraction in dark matter $f_\textrm{max}$ versus the PBH mass $M_{\rm PBH}$ from the nondetection of the SGWB from Advanced LIGO's O1 and the expected constraints based on the O2 and O5 projected sensitivities. These constraints are compared to those from star microlensing Novati:2013fxa, quasar microlensing Mediavilla:2009um, dynamics of dwarf galaxies Koushiappas:2017chw and accretion effects on CMB Ali-Haimoud:2016mbv. The local merger rate for GW150914- and GW151226-like BBH can also constrain the PBH abundance with corresponding mass.
• Figure 2: The SGWB spectra from subsolar mass binary PBH mergers at the current best constraints from stellar microlensing. Nondetection in Advanced LIGO's O2 can further constrain the existence of subsolar mass PBH.