Multiband gravitational wave observations of eccentric escaping binary black holes from globular clusters

TL;DR

This paper investigates how multiband gravitational wave detectors can observe and characterize eccentric binary black holes escaping from globular clusters, providing insights into their formation and evolution.

Contribution

It introduces a comprehensive simulation framework combining globular cluster models with cosmological data to evaluate multiband GW detection prospects for eccentric black hole binaries.

Findings

LISA, Taiji, LT, and AMIGO can detect dozens of escaping sBBHs over four years.

Eccentricities can be measured with high precision, especially by LT and LT-AMIGO.

Multiband observations significantly improve parameter estimation for eccentric binary black holes.

Abstract

Stellar-mass binary black holes (sBBHs) formed in globular clusters (GCs) are promising sources for multiband gravitational wave (GW) observations, particularly with low- and middle-frequency detectors. These sBBHs can retain detectable eccentricities when they enter the sensitivity bands of low-frequency GW observatories. We study multiband GW observations of eccentric sBBHs that escape from GC models simulated with the MOCCA code, focusing on how low- and middle-frequency detectors can constrain their eccentricities and other parameters. Using Monte Carlo simulations, we generate ten realizations of cosmic sBBHs by combining the MOCCA sample with a cosmological model for GC formation and evolution. We then assess their detectability and the precision of parameter estimation. Our results show that LISA, Taiji, the LISA-Taiji network (LT), and AMIGO could detect $0.8\pm0.7$, $11.6\pm2.0$, $15.4\pm2.7$, and $7.9\pm1.3$ escaping sBBHs, respectively, over four years, while LT-AMIGO could detect $20.6\pm3.0$ multiband sBBHs in the same period. LT and AMIGO can measure initial eccentricities with relative errors of approximately $10^{-6}-2\times10^{-4}$ and $10^{-3}-0.7$, respectively. Joint LT-AMIGO observations have a similar ability to estimate eccentricities as LT alone.