Spinformation: do gravitational-wave events carry information beyond effective spins?
Abstract
While the spin vectors of binary black holes offer insight into the astrophysical formation channels of these systems, individual spins are less precisely measured through gravitational-wave observations than the effective inspiral spin χeff and the effective precession spin χp. Reducing to effective parameters discards information in the data, but how much information is lost has yet to be demonstrated. Here we show how to quantify whether individual mergers carry information about component spins beyond the constraints implied by effective parameters (a.k.a. spinformation) and apply the technique to GWTC-5. Thresholding on information loss ≳ 0.25 bits, over 80% of gravitational-wave events in GWTC-5 have component spin posteriors described by χeff alone. Only ∼3% of gravitational-wave events have substantial spin information not explained by χeff and χp. The catalog's component spin information is effectively two-dimensional in χeff and χp. Using simulated signals, we find the noise realization can create or destroy over a bit of beyond-χeff information: the structure in real data may therefore be driven by noise. At current sensitivity, component spins provide interpretive\textemdash rather than informational\textemdash advantage over effective parameters.
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BibTeX
@misc{plunkett2026spinformation,
title = {{Spinformation: do gravitational-wave events carry information beyond effective spins?}},
author = {Cailin Plunkett and Jack Heinzel and Noah E. Wolfe and Davide Gerosa and Salvatore Vitale},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.18973},
eprint = {2610.18973},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.18973},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Spinformation: do gravitational-wave events carry information beyond effective spins?
AU - Cailin Plunkett
AU - Jack Heinzel
AU - Noah E. Wolfe
AU - Davide Gerosa
AU - Salvatore Vitale
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.18973
UR - https://arxiv.org/abs/2610.18973
AB - While the spin vectors of binary black holes offer insight into the astrophysical formation channels of these systems, individual spins are less precisely measured through gravitational-wave observations than the effective inspiral spin χ_eff and the effective precession spin χ_p. Reducing to effective parameters discards information in the data, but how much information is lost has yet to be demonstrated. Here we show how to quantify whether individual mergers carry information about component spins beyond the constraints implied by effective parameters (a.k.a. spinformation) and apply the technique to GWTC-5. Thresholding on information loss ≳ 0.25 bits, over 80% of gravitational-wave events in GWTC-5 have component spin posteriors described by χ_eff alone. Only ∼3% of gravitational-wave events have substantial spin information not explained by χ_eff and χ_p. The catalog's component spin information is effectively two-dimensional in χ_eff and χ_p. Using simulated signals, we find the noise realization can create or destroy over a bit of beyond-χ_eff information: the structure in real data may therefore be driven by noise. At current sensitivity, component spins provide interpretive\textemdash rather than informational\textemdash advantage over effective parameters.
ER -