Gravitational wave constraints on planetary-mass primordial black holes using LIGO O3a data

Understand

Gravitational waves from sub-solar mass inspiraling compact objects would provide almost smoking-gun evidence for primordial black holes (PBHs).

• We perform the first search for inspiraling planetary-mass compact objects in equal-mass and highly asymmetric mass-ratio binaries using data from the first half of the LIGO-Virgo-KAGRA third observing run.
• Though we do not find any significant candidates, we determine the maximum luminosity distance reachable with our search to be of $O(0.1-100)$ kpc, and corresponding model-independent upper limits on the merger rate densities to be $O(10^{3}-10^{-7})$ kpc$^{-3}$yr$^{-1}$ for systems with chirp masses of $O(10^{-4}-10^{-2})M_\odot$, respectively.
• Furthermore, we interpret these rate densities as arising from PBH binaries and constrain the fraction of dark matter that such objects could comprise.