Antialigned spin of GW191109: Glitch mitigation and its implications
Abstract
With a high total mass and an inferred effective spin antialigned with the orbital axis at the 99.9% level, GW191109 is one of the most promising candidates for a dynamical formation origin among gravitational wave events observed so far. However, the data containing GW191109 are afflicted with terrestrial noise transients, i.e., detector glitches, generated by the scattering of laser light in both LIGO detectors. We study the implications of the glitch(es) on the inferred properties and astrophysical interpretation of GW191109. Using time- and frequency-domain analysis methods, we isolate the critical data for spin inference to 35–40 Hz and 0.1–0.04 s before the merger in LIGO Livingston, directly coincident with the glitch. Using two models of glitch behavior, one tailored to slow scattered light and one more generic, we perform joint inference of the glitch and binary parameters. When the glitch is modeled as slow scattered light, the binary parameters favor antialigned spins, in agreement with existing interpretations. When more flexible glitch modeling based on sine-Gaussian wavelets is used instead, a bimodal aligned/antialigned solution emerges. The antialigned spin mode is correlated with a weaker inferred glitch and preferred by ∼70 :30 compared to the aligned spin mode and a stronger inferred glitch. We conclude that if we assume that the data are only impacted by slow scattering noise, then the antialigned spin inference is robust. However, the data alone cannot validate this assumption and resolve the antialigned spin and potentially dynamical formation history of GW191109.
Copyright and License
© 2025 American Physical Society.
Acknowledgement
We thank Jess McIver, Niko Lecoeuche, Eric Thrane, Paul Lasky, Hui Tong, Maya Fishbach, Ethan Payne, and Jacob Golomb for helpful discussions about this analysis. We thank Lucy Thomas and Aaron Zimmerman for insightful discussions on the behavior of merger dominated waveforms and the 𝜒eff −𝐷𝐿 degeneracy. We thank Isobel Romero-Shaw and Tousif Islam for assistance with accessing and interpreting previous analyses. We thank Colm Talbot for assistance in the implementation of glitch inference in bilby. We thank Carl-Johan Haster for helpful comments on the manuscript. R. U. and D. D. are supported by NSF Grant No. PHY-2309200. S. M., S. H., H. D., and K. C. were supported by NSF Grant No. PHY-2110111 and NSF Grant No. PHY-2308770. S. H. was supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. This work was partially supported by the generosity of Eric and Wendy Schmidt by recommendation of the Schmidt Futures program. The Flatiron Institute is funded by the Simons Foundation. 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 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.
Files
Name | Size | Download all |
---|---|---|
md5:67714c981acb4ad14d85444bfb4860f9
|
6.9 MB | Preview Download |
Additional details
- Alternative title
- The anti-aligned spin of GW191109: glitch mitigation and its implications
- National Science Foundation
- PHY-2309200
- National Science Foundation
- PHY-2110111
- National Science Foundation
- PHY-2308770
- National Science Foundation
- DGE-1745301
- National Science Foundation
- PHY-0757058
- Schmidt Futures
- Simons Foundation
- National Science Foundation
- PHY-0823459
- Accepted
-
2024-12-11Accepted
- Caltech groups
- Astronomy Department, LIGO
- Publication Status
- Published