A pipeline to search for signatures of line-of-sight acceleration in gravitational wave signals produced by compact binary coalescences

TL;DR

This paper develops a pipeline to detect line-of-sight acceleration signatures in gravitational wave signals from compact binary mergers, incorporating Post-Newtonian corrections into waveform models and testing their robustness in parameter estimation.

Contribution

It introduces a method to include LOSA effects in GW waveform models and integrates this into existing parameter estimation software, enabling systematic searches for environmental influences on GW signals.

Findings

LOSA can be recovered accurately when waveform models match injections.

The pipeline is robust against higher-mode and beyond-GR waveform signatures.

Limits of applicability for LOSA detection are established.

Abstract

Compact binary coalescences (CBCs), such as merging binary black holes (BBHs), binary neutron stars (BNSs), or neutron star black holes (NSBHs), hosted by dense stellar environments, could produce gravitational waves (GWs) that contain signatures of line-of-sight acceleration (LOSA) imparted by the environment's gravitational potential. We calculate the Post-Newtonian (PN) corrections to the $(2,\,2)$ mode GW phase due to a finite LOSA, starting from the leading order at -4 PN below the quadrupole order, up to 3.5 PN above the quadrupole order. We do so for binaries whose component spins are aligned with the orbital angular momentum, as well as for binaries with non-zero tidal deformation. We implement these corrections into the LIGO-Virgo-Kagra (LVK) collaboration's flagship parameter estimation (PE) software \textsc{Bilby\_tgr}. We study the systematics associated with recovering LOSAs. We find that, when the injection and recovery waveform models are identical, LOSAs are recovered as expected. We test the robustness of the pipeline against waveforms with strong higher-mode signatures or signatures of beyond-general-relativistic (beyond-GR) effects, to delimit the range of applicability of our GR-consistent quasi-circular LOSA-corrected waveforms.