2023 Winner

Ansel Neunzert is currently a postdoctoral scholar at LHO and affiliate instructor at the University of Washington, Bothell. Their work focuses on improving detection prospects for continuous gravitational wave searches and other long-duration analyses. They have also worked on projects related to detector calibration and continuous-wave search methods. Outside of LIGO, Neunzert has a strong interest in physics pedagogy.

The LIGO Laboratory congratulates Ansel Neunzert of LIGO Hanford Observatory and Caltech, for winning the 2023 LIGO Laboratory Award for Excellence in Detector Characterization and Calibration.

This year's award recognizes Neunzert's work on speeding up and automating finding and tracking "line" and "comb" noise features in LIGO detector data. These lines represent very steady features in the data (like the sound from a tuning fork) and can severely impact searches for long-duration gravitational-wave sources, including spinning neutron stars in our own Milky Way galaxy. Previously, lists of lines were generated by time-consuming visual inspection of spectra by experts only once per observing run. After lines were found, more human effort was necessary to identify “combs”, or groups of equally-spaced lines in the frequency space, which can be important clues to possible sources of the noise. Now, Neunzert’s codes produce a thorough, automated analysis daily, weekly, and monthly, as well as at specific times when requested. Their work has vastly reduced the time to identify and eventually mitigate these noise features. 

Neunzert’s work is already positively impacting O4 data quality. One example is a 1.66Hz comb structure in the Hanford instrument that Neunzert identified. After iterations of targeted changes in the hardware configurations by the instrument scientists at the site, and Neunzert's quick reanalysis of the interferometer data, this newly found comb was traced to the temperature monitor system for one of the relay mirrors in the LIGO Hanford instrument. The configuration of the offending monitor was changed, and as a result, the comb was eliminated from the data, removing these noise artifacts and increasing our ability to search for long-duration gravitational-wave sources near these former lines.

An illustration of “line” and “comb” features in LIGO Hanford data, shown in black. The y-axis shows the amplitude of detector noise and the x-axis represents frequency (where low frequencies are deeper in pitch, like a tuba, and higher frequencies are more like a piccolo). The spiky features standing above the noise curve are called lines. The multi-line structures labeled with specific colors and shapes (for example, a yellow triangle or a pink diamond) are called combs, and each comb most likely represents a single source of noise.

This important effort may also potentially enable a first detection of long-duration gravitational waves from the Milky Way by the LIGO detectors. 

For their work, Neunzert 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 their achievements with LIGO Laboratory members. Neunzert will also be presented with an award certificate at the next meeting of the LIGO-Virgo-KAGRA collaboration.

Read more about Ansel Neunzert’s work and related efforts:

[1] D Davis et al. (2021) Class. Quantum Grav. 38 135014. LIGO detector characterization in the second and third observing runs. https://iopscience.iop.org/article/10.1088/1361-6382/abfd85/ampdf

[2] P. B. Covas et al. (2018) Phys. Rev. D 97, 082002. Identification and mitigation of narrow spectral artifacts that degrade searches for persistent gravitational waves in the first two observing runs of Advanced LIGO. https://journals.aps.org/prd/abstract/10.1103/PhysRevD.97.082002

[3] Riles, K. (2023) Living Rev Relativ 26, 3. Searches for continuous-wave gravitational radiation. https://link.springer.com/article/10.1007/s41114-023-00044-3

2023 Honorable Mentions

The LIGO Laboratory is also pleased to list five other projects meriting honorable mention

Louis Dartez (Caltech, LIGO Hanford) - for delivering and testing a low latency estimation of the systematic error for LIGO’s calibrated data. 

Jane Glanzer (Louisiana State University) - for diagnosing scatter noise couplings at LIGO Livingston.

Adrian F. Helmling-Cornell (University of Oregon) - for characterizing the impact of environmental noise on gravitational wave science.

Sophie Hourihane (Caltech) - for further advances in glitch subtraction related to compact binary parameter estimation. 

Ronaldas Macas (University of Portsmouth) - for Improving event validation and noise mitigation for LIGO-Virgo’s fourth observing run.