2021 Winner

The LIGO Laboratory congratulates Ethan Payne of Caltech for winning this year’s LIGO Laboratory Award for Excellence in Detector Characterization and Calibration for his pivotal role in improving gravitational wave source parameter estimation by enabling more accurate incorporation of systematic detector calibration errors [1].

Ethan Payne is a first year PhD student at the California Institute of Technology. He graduated with a Bachelor’s degree from Monash University (Australia) in 2020. In early 2021, he worked as a research assistant for both Monash University and the Australian National University. As part of the LSC’s Calibration group, Ethan explores the interface between observed gravitational-wave signals and calibration uncertainty in LIGO’s detectors. He is also interested in exploring astrophysical populations and testing fundamental physics with gravitational waves, and the role detector calibration plays in these areas. In his free time, Ethan enjoys rock climbing and cycling around Pasadena. (Photo credit: Alvin Li)

Payne surpassed long-standing technical hurdles to allow estimation of systematic calibration error to be easily ingested by astrophysical analyses. To estimate the gravitational wave strain, raw output of the detector is first filtered using a complex detector model that contains many physical parameters with uncertainties [2]. If the model fails to accurately describe the behavior of the detector, including uncertainties, this introduces systematic error into gravitational wave strain data used for astrophysical analyses [3].

Estimating the astrophysical parameters of gravitational wave sources from gravitational wave detector data is a computationally expensive process deeply impacted by analytical uncertainties arising from detectors’ background noise as well as potential calibration error [4]. For the important latter case, until recently, only light-weight statistical approximations that do not utilize critical characteristics of detector calibration error had been used in the astrophysical parameter estimation process [5].

Payne wins this year’s award for his leading role in breaking down this multifaceted computational barrier. The calibration software infrastructure he developed allowed for calibration error estimates to be smoothly integrated into source property estimation pipelines Bilby and RIFT and drastically reduced the computational cost of accounting for calibration error. Payne’s work was deployed in the LIGO-Virgo-KAGRA collaboration’s results for O3, recently released in the latest gravitational wave event catalog GWTC-3 [7] and companion papers. Payne also led a study showing there was a negligible impact of calibration uncertainty on the parameter estimation of detections in the first two Advanced LIGO and Advanced Virgo observing runs, O1 and O2, (GWTC-2), with hints that current uncertainty levels could impact analysis of future loud binary black hole detections [1].

Payne’s breakthrough unlocks the ability to easily study when and how detector calibration error will impact astrophysical parameter estimation for future gravitational wave detections. His effort significantly improves our ability to perform precision tests of fundamental physics and probe new frontiers in astrophysics with gravitational waves.

Payne will receive a $1,000 prize and present an invited seminar at one of the LIGO Laboratory sites (LIGO-Hanford, LIGO-Livingston, Caltech, or MIT) to share his achievements with LIGO Laboratory members. Payne will also be presented with an award certificate at the next meeting of the LIGO-Virgo-KAGRA collaboration.

Read more about Ethan Payne's work and related efforts:

[1] Payne, Ethan, et al. "Gravitational-wave astronomy with a physical calibration model." Physical Review D 102.12 (2020): 122004. arXiv: https://arxiv.org/abs/2009.10193
[2] Viets, A. D., et al. "Reconstructing the calibrated strain signal in the Advanced LIGO detectors." Classical and Quantum Gravity 35.9 (2018): 095015. arXiv: https://arxiv.org/abs/1710.09973
[3] Sun, Ling, et al. "Characterization of systematic error in Advanced LIGO calibration." Classical and Quantum Gravity 37.22 (2020): 225008. arXiv: https://arxiv.org/abs/2005.02531
[4] Abbott, Benjamin P., et al. "Properties of the binary black hole merger GW150914." Physical review letters 116.24 (2016): 241102. arXiv: https://arxiv.org/abs/1602.03840
[5] W. M. Farr, B. Farr, and T. Littenberg, Tech. Rep. LIGO-T1400682 (LIGO Project, 2015)
[6] Vitale, Salvatore, et al. "Physical approach to the marginalization of LIGO calibration uncertainties." Physical Review D 103.6 (2021): 063016. arXiv: https://arxiv.org/abs/2009.10192
[7] Abbott, R., et al. "GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run." Submitted to PRX (2021). arXiv: https://arxiv.org/abs/2111.03606

2021 Honorable Mention

The LIGO Laboratory is also pleased to recognize one other project as meriting honorable mention:

Philippe Nguyen (University of Oregon) -- for a leading role in understanding how environmental conditions couple to and limit the sensitivity of the LIGO detectors during their third observing run.