Search for gravitational waves from the coalescence of sub-solar mass binaries in the first half of Advanced LIGO and Virgo's third observing run

TL;DR

This study searches for gravitational waves from sub-solar mass black hole mergers in LIGO and Virgo data, aiming to detect primordial black holes that could contribute to dark matter, but finds no candidates and sets new upper limits.

Contribution

It provides the first comprehensive search for sub-solar mass black hole mergers in the third LIGO-Virgo observing run, establishing new upper limits and constraining primordial black hole models.

Findings

No convincing gravitational wave candidates found.

Set upper limits on merger rates of sub-solar mass black holes.

Limits are 3-4 times more restrictive than previous analyses.

Abstract

We present a search for gravitational waves from the coalescence of sub-solar mass black hole binaries using data from the first half of Advanced LIGO and Virgo's third observing run. The observation of a sub-solar mass black hole merger may be an indication of primordial origin; primordial black holes may contribute to the dark matter distribution. We search for black hole mergers where the primary mass is $0.1-7 M_{\odot}$ and the secondary mass is $0.1-1 M_{\odot}$. A variety of models predict the production and coalescence of binaries containing primordial black holes; some involve dynamical assembly which may allow for residual eccentricity to be observed. For component masses $>0.5 M_{\odot}$, we also search for sources in eccentric orbits, measured at a reference gravitational-wave frequency of 10 Hz, up to $e_{10}\sim 0.3$. We find no convincing candidates and place new upper limits on the rate of primordial black hole mergers. The merger rate of 0.5-0.5 (1.0-1.0)~$M_{\odot}$ sources is $<7100~(1200)$ Gpc$^{-3}$yr$^{-1}$. Our limits are $\sim3-4$ times more constraining than prior analyses. Finally, we demonstrate how our limits can be used to constrain arbitrary models of the primordial black hole mass distribution and merger rate.