GW240925 and GW250207 are two loud gravitational-wave signals from binary black hole coalescences observed with network signal-to-noise ratios \$\textbackslash{}sim 32\$ and \$\textbackslash{}sim 69\$, respectively, by the LIGO Hanford--LIGO Livingston--Virgo network. Gravitational-wave signals from coalescing binaries have characteristic phase and amplitude evolution predicted by general relativity. These signal waveforms, together with measured instrumental calibration uncertainties, are used to infer source parameters. However, for sufficiently loud detections it is possible to constrain the calibration of the detectors directly using the signals themselves. We present the first informative astrophysical measurements of gravitational-wave detector calibration. For GW240925, we verify the inference of Hanford calibration from the astrophysical signal through cross-checks with known calibration errors obtained from in-situ measurements. At the time of GW250207, the Hanford detector was not fully stabilized, leading to elevated calibration uncertainties; thus, astrophysical calibration is essential to obtain accurate data and to enable source localization. These well-localized, high signal-to-noise observations have the potential to offer precise measurements of source properties, stringent tests of general relativity, and informative dark siren measurements, provided that calibration uncertainties are properly incorporated. As detector sensitivity improves, astrophysical calibration will become an increasingly valuable complement to in-situ calibration measurements. Obtaining accurate calibration will be essential for precision gravitational-wave science.
LIGO Scientific, Virgo, KAGRA Collaborations & Van den Bossche, E 2026, 'GW240925 and GW250207: Astrophysical Calibration of Gravitational-wave Detectors', Phys. Rev. Lett., vol. 2026, no. 137, 071401. https://doi.org/10.1103/gzrj-mwv3
LIGO Scientific, Virgo, KAGRA Collaborations, & Van den Bossche, E. (2026). GW240925 and GW250207: Astrophysical Calibration of Gravitational-wave Detectors. Phys. Rev. Lett., 2026(137), Article 071401. https://doi.org/10.1103/gzrj-mwv3
@article{2110e96311dd4b5a95ab1c5ee7106549,
title = "GW240925 and GW250207: Astrophysical Calibration of Gravitational-wave Detectors",
abstract = "GW240925 and GW250207 are two loud gravitational-wave signals from binary black hole coalescences observed with network signal-to-noise ratios \$\textbackslash{}sim 32\$ and \$\textbackslash{}sim 69\$, respectively, by the LIGO Hanford--LIGO Livingston--Virgo network. Gravitational-wave signals from coalescing binaries have characteristic phase and amplitude evolution predicted by general relativity. These signal waveforms, together with measured instrumental calibration uncertainties, are used to infer source parameters. However, for sufficiently loud detections it is possible to constrain the calibration of the detectors directly using the signals themselves. We present the first informative astrophysical measurements of gravitational-wave detector calibration. For GW240925, we verify the inference of Hanford calibration from the astrophysical signal through cross-checks with known calibration errors obtained from in-situ measurements. At the time of GW250207, the Hanford detector was not fully stabilized, leading to elevated calibration uncertainties; thus, astrophysical calibration is essential to obtain accurate data and to enable source localization. These well-localized, high signal-to-noise observations have the potential to offer precise measurements of source properties, stringent tests of general relativity, and informative dark siren measurements, provided that calibration uncertainties are properly incorporated. As detector sensitivity improves, astrophysical calibration will become an increasingly valuable complement to in-situ calibration measurements. Obtaining accurate calibration will be essential for precision gravitational-wave science.",
keywords = "gr-qc, astro-ph.HE, astro-ph.IM",
author = "\{LIGO Scientific, Virgo, KAGRA Collaborations\} and A. Adam and D. Adhikari and Adhikari, \{R. X.\} and W. Ali and G. Baldi and Bell, \{A. S.\} and Blair, \{C. D.\} and S. Bose and H. Cao and S. Chakraborty and C. Chan and Chan, \{J. C. L.\} and D. Chen and H. Chen and H. Chen and S. Chen and Y. Chen and C. Chou and N. Christensen and Clark, \{J. A.\} and Collette, \{C. G.\} and A. Colombo and L. Conti and Cullen, \{T. J.\} and Davis, \{M. C.\} and P. Davis and Bolle, \{J. De\} and D{\'i}az, \{M. C.\} and J. Ding and M. Dubois and H. Duval and M. Esposito and M. Gosselin and H. Guo and W. Guo and Y. Guo and Gupta, \{N. C.\} and Gupta, \{S. K.\} and N. Gutierrez and Huang, \{H. Y.\} and Y. Huang and Y. Huang and M. Jain and T. Jain and James, \{A. L.\} and M. Jensen and J. Jiang and Jin, \{H. -B.\} and Jones, \{D. H.\} and Jones, \{D. H.\} and Joshi, \{S. K.\} and Kim, \{J. C.\} and Kim, \{M. H.\} and S. Kim and Kim, \{Y. -M.\} and M. Lalleman and Lee, \{H. W.\} and J. Lee and K. Lee and Lee, \{Y. S. C.\} and Lee, \{Y. S. C.\} and Li, \{K. L.\} and Li, \{T. G. F.\} and X. Li and Y. Li and Z. Li and Lin, \{Y. -C.\} and Liu, \{G. C.\} and Jian Liu and S. Liu and S. Ma and X. Ma and A. Malik and M. Mantovani and Martin, \{R. M.\} and Martins, \{J. C.\} and C. Michel and Miller, \{S. J.\} and Mitchell, \{A. L.\} and S. More and Muller, \{A. R.\} and S. Ng and A. Pal and S. Pal and H. Pan and A. Parisi and S. Peters and H. Pham and M. Pinto and Pradhan, \{B. K.\} and J. Qin and S. Raja and M. Ricci and Richardson, \{J. W.\} and Richardson, \{M. L.\} and A. Romero-Rodr{\'i}guez and S. Roy and S. Roy and S. Saha and M. Sakellariadou and A. Sanchez and Sanchez, \{E. J.\} and Sanders, \{J. R.\} and P. Schmidt and Sengupta, \{A. S.\} and A. Sevrin and Shaikh, \{M. A.\} and Singh, \{M. K.\} and N. Singh and S. Singh and Smith, \{D. A.\} and L. Smith and Smith, \{R. J. E.\} and I. Song and V. Sordini and P. Stevens and J. Sun and L. Sun and K. Tanaka and Tanaka, \{S. J.\} and Thomas, \{L. M.\} and M. Thomas and P. Thomas and K. Turbang and \{van Dael\}, M. and \{den Bossche\}, \{E. Van\} and Broeck, \{C. Van Den\} and \{de Walle\}, \{A. Van\} and \{van Dongen\}, J. and M. Vereecken and Vermeulen, \{S. M.\} and Vincent, \{E. T.\} and Wang, \{E. J.\} and H. Wang and Wang, \{W. H.\} and Wang, \{Y. F.\} and Z. Wang and Williams, \{M. J.\} and M. Wils and Wong, \{H. T.\} and T. Wouters and Wright, \{J. L.\} and C. Wu and Wu, \{D. S.\} and H. Wu and K. Wu and Q. Wu and Z. Wu and Y. Xu and N. Yadav and H. Yang and Y. Yang and M. Zeeshan and H. Zhang and L. Zhang and T. Zhang and C. Zhao and Zhao, \{Z. -C.\} and Y. Zheng and Zhu, \{H. O.\} and \{Van den Bossche\}, Elise",
note = "38 pages (11 pages author list, 7 pages main paper, 8 pages references, 12 pages supplemental material), 15 figures (4 in main text, 11 in supplemental material); data products available from https://doi.org/10.5281/zenodo.18600070",
year = "2026",
month = aug,
day = "13",
doi = "10.1103/gzrj-mwv3",
language = "English",
volume = "2026",
journal = "Phys. Rev. Lett.",
issn = "0031-9007",
publisher = "American Physical Society",
number = "137",
}