oai:arXiv.org:2405.14945
sciences: astrophysics
2024
10/2/2024
Resolving the formation channel(s) of merging binary black holes is a key goal in gravitational-wave astronomy.
The orbital eccentricity is believed to be a precious tracer of the underlying formation pathway, but is largely dissipated during the usually long inspiral between black hole formation and merger.
Most gravitational-wave sources are thus expected to enter the sensitivity windows of current detectors on configurations that are compatible with quasi-circular orbits.
In this paper, we investigate the impact of "negligible" residual eccentricity -- lower than currently detectable by LIGO/Virgo -- on our ability to infer the formation history of binary black holes, focusing in particular on their spin orientations.
We trace the evolution of both observed and synthetic gravitational-wave events backward in time, while resampling their residual eccentricities to values that are below the detectability threshold.
Eccentricities in-band as low as $\sim 10^{-4}$ can lead to significant biases when reconstructing the spin directions, especially in the case of loud, highly precessing systems.
Residual eccentricity thus act like a systematic uncertainty for our astrophysical inference.
As a mitigation strategy, one can marginalize the posterior distribution over the residual eccentricity using astrophysical predictions.
;Comment: 10 pages, 4 figures, 2 tables
Fumagalli, Giulia,Romero-Shaw, Isobel,Gerosa, Davide,De Renzis, Viola,Kritos, Konstantinos,Olejak, Aleksandra, 2024, Residual eccentricity as a systematic uncertainty on the formation channels of binary black holes