Distinguishing black-hole spin-orbit resonances by their gravitational wave signatures. II: Full parameter estimation

TL;DR

This paper performs detailed parameter estimation on binary black hole systems to distinguish different spin-orbit resonances using gravitational wave signatures, introducing new variables for better dynamical encoding.

Contribution

It introduces a comprehensive parameter estimation framework for resonant binaries and new variables that capture the dynamical timescale separation in precessing black hole systems.

Findings

Resonances can be distinguished across a wide range of binary configurations.

Highly symmetric configurations suppress precessional effects, making resonance identification challenging.

New variables improve the encoding of dynamical information in gravitational wave analysis.

Abstract

Gravitational waves from coalescing binary black holes encode the evolution of their spins prior to merger. In the post-Newtonian regime and on the precession timescale, this evolution has one of three morphologies, with the spins either librating around one of two fixed points ("resonances") or circulating freely. In this work we perform full parameter estimation on resonant binaries with fixed masses and spin magnitudes, changing three parameters: a conserved "projected effective spin" $\xi$ and resonant family $\Delta\Phi=0,\pi$ (which uniquely label the source), the inclination $\theta_{JN}$ of the binary's total angular momentum with respect to the line of sight (which determines the strength of precessional effects in the waveform), and the signal amplitude. We demonstrate that resonances can be distinguished for a wide range of binaries, except for highly symmetric configurations where precessional effects are suppressed. Motivated by new insight into double-spin evolution, we introduce new variables to characterize precessing black hole binaries which naturally reflects the timescale separation of the system and therefore better encode the dynamical information carried by gravitational waves.