Spectroscopic analysis of stellar mass black-hole mergers in our local universe with ground-based gravitational wave detectors

TL;DR

This study evaluates the potential of current and future ground-based gravitational wave detectors to perform spectroscopic analysis of black-hole merger ringdowns, focusing on the detectability of sub-dominant modes to test black hole physics.

Contribution

It provides a comprehensive analysis of the prospects for measuring multiple ringdown modes in stellar mass black-hole mergers with various ground-based detectors, including upgrades and future facilities.

Findings

Advanced LIGO can measure about 3 events per year with optimistic rates.

Future detectors like Einstein Telescope could measure thousands of events annually.

Modes with l=m=3 and l=2, m=1 are most promising for sub-dominant mode detection.

Abstract

Motivated by the recent discoveries of binary black-hole mergers by the Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO), we investigate the prospects of ground-based detectors to perform a spectroscopic analysis of signals emitted during the ringdown of the final Kerr black-hole formed by a stellar mass binary black-hole merger. If we assume an optimistic rate of 240 Gpc$^{-3}$yr$^{-1}$, about 3 events per year can be measured by Advanced LIGO. Further, upgrades to the existing LIGO detectors will increase the odds of measuring multiple ringdown modes significantly. New ground-based facilities such as Einstein Telescope or Cosmic Explorer could measure multiple ringdown modes in about thousand events per year. We perform Monte-Carlo injections of $10^{6}$ binary black-hole mergers in a search volume defined by a sphere of radius 1500 Mpc centered at the detector, for various proposed ground-based detector models. We assume a uniform random distribution in component masses of the progenitor binaries, sky positions and orientations to investigate the fraction of the population that satisfy our criteria for detectability and resolvability of multiple ringdown modes. We investigate the detectability and resolvability of the sub-dominant modes $l=m=3$, $l=m=4$ and $l=2, m=1$. Our results indicate that the modes with $l=m=3$ and $l=2, m=1$ are the most promising candidates for sub-dominant mode measurability. We find that for stellar mass black-hole mergers, resolvability is not a limiting criteria for these modes. We emphasize that the measurability of the $l=2, m=1$ mode is not impeded by the resolvability criterion.