Phase consistency test to identify type II strongly lensed gravitational-wave signals using a single event
- Creators
-
Taylor, Kelsie1
-
Davis, Derek2
-
Lo, Rico K. L.3
-
1.
The University of Texas at Austin
-
2.
California Institute of Technology
-
3.
University of Copenhagen
Abstract
For gravitationally lensed type II signals, the phase of the dominant (2, 2) mode and the higher-order (3, 3) mode is offset by −𝜋/12, or roughly −0.26 rad. Using this, we develop a test for type II imagery by allowing the phases of the (2, 2) and (3, 3) modes to vary separately and introducing a new waveform parameter to represent the phase offset between the two. We use simulated, asymmetric mass ratio, precessing signals to show that the test can reproduce the −𝜋/12 phase offset when detected by three detectors for H-L optimal SNR≳40 and ℳ ≤30. We analyze GW190412 and GW190814 using this parametrization, measuring the offset to be 0.13+0.22−0.17 for GW190412 and −0.05+0.20−0.22 for GW190814. We also measure the Bayes factor in support of zero phase offset, log10 ℬΔ𝜑=0, to be −0.14 for GW190412 and 0.21 for GW190814. This implies our results are not strong enough to confidently argue if either event is a type II image and is consistent with our statistical analysis.
Copyright and License
© 2025 American Physical Society.
Acknowledgement
We thank Alan Weinstein for support and helpful discussions throughout this project. We thank Katerina Chatziioannou for discussions related to the expected phase behavior of type II images and Lucy Thomas for her input on waveform choices and parameter estimation. We thank Mick Wright for helpful comments during internal review of this work. K. T. and D. D. acknowledge support from the National Science Foundation (NSF) through the LIGO Laboratory. K. T. also acknowledges support from the US DoD through the NDSEG fellowship. R. K. L. L. acknowledges support from the research Grants No. VIL37766 and No. VIL53101 by the Villum Fonden, the DNRF Chair program Grant No. DNRF162 by the Danish National Research Foundation, the European Union’s Horizon 2020 research and the innovation program under the Marie Sklodowska-Curie Grant Agreement No. 101131233. The Center of Gravity is a Center of Excellence funded by the Danish National Research Foundation under Grant No. 184. This material is based upon work supported by NSF’s LIGO Laboratory which is a major facility fully funded by the National Science Foundation. LIGO was constructed by the California Institute of Technology and Massachusetts Institute of Technology with funding from the National Science Foundation and operates under Cooperative Agreement No. PHY-2309200. The authors are grateful for computational resources provided by the LIGO Laboratory and supported by National Science Foundation Grants No. PHY-0757058 and No. PHY-0823459.
Data Availability
The data that support the findings of this article are openly available:
K. Taylor, D. Davis, and R. Lo, Phase consistency test to identify type II strongly lensed gravitational-wave signals using a single event, 10.5281/zenodo.15786856 (2025).
Files
| Name | Size | Download all |
|---|---|---|
|
md5:b17e0413a8a1bb1d95893a9237d4028c
|
1.3 MB | Preview Download |
Additional details
- United States Department of Defense
- NDSEG fellowship -
- National Science Foundation
- PHY-2309200
- National Science Foundation
- PHY-0757058
- National Science Foundation
- PHY-0823459
- Villum Fonden
- VIL37766
- Villum Fonden
- VIL53101
- Danish National Research Foundation
- DNRF Chair program DNRF162
- European Union
- Horizon 2020 Marie Sklodowska-Curie Grant Agreement 101131233
- Caltech groups
- LIGO, Division of Physics, Mathematics and Astronomy (PMA)
- Publication Status
- Published