Research

I develop gravitational-wave data-analysis methods for real-time detection, sky localization, and searches for strongly lensed signals.

My work is motivated by a central problem in gravitational-wave astronomy: many scientifically valuable signals are difficult to identify with standard single-event searches. These include subthreshold events, repeated signals from gravitational lensing, microlensing signatures, and signals whose interpretation depends on rapid multi-messenger follow-up. I work on methods that combine low-latency detection systems, targeted searches, cross-event consistency, and astrophysical priors. A more visual overview of the same themes is on the Interests page.

Primary areas Low-latency detection, gravitational-wave lensing, sky localization
Collaboration role Co-chair, KAGRA Low-Latency Group
Methods TESLA/TESLA-X, GstLAL workflows, targeted searches, cross-event inference

Research Directions

01

Targeted searches for lensed gravitational waves

I pioneered the TESLA framework and led the development of TESLA-X, targeted search methods designed to recover subthreshold lensed gravitational-wave signals using information from known events. These methods reduce the effective search space while preserving sensitivity to physically consistent lensed counterparts.

02

Low-latency detection and alert infrastructure

As co-chair of the KAGRA Low-Latency Group, I coordinate real-time gravitational-wave detection and alert workflows for multi-messenger follow-up. This includes pipeline integration, validation, and readiness work for LVK observing runs.

03

Sky localization and multi-messenger astronomy

I study how detector geometry, sensitivity, and repeated images affect sky localization. This work supports rapid electromagnetic follow-up, host-galaxy identification, and the use of lensed gravitational waves as probes of astrophysics and cosmology.

04

Statistically robust lensing analyses

I work on validation, background estimation, and significance evaluation for gravitational-wave lensing candidates, including mock-data challenges and collaboration-wide analyses for LVK observing runs.

Selected Publications

Investigating the effect of sensitivity of KAGRA on sky localization of gravitational-wave sources from compact binary coalescences

Alvin K. Y. Li, Peony K. K. Lai, Elwin K. Y. Li, Otto A. Hannuksela

arXiv:2604.13580, 2026

A first investigation of repeated-signal localization of strongly lensed gravitational waves for multimessenger astronomy

Alvin K. Y. Li, Otto A. Hannuksela

arXiv:2604.16561, 2026

TESLA-X: an effective method to search for subthreshold lensed gravitational waves with a targeted population model

Alvin K. Y. Li, Juno C. L. Chan, Heather Fong, Aidan H. Y. Chong, Alan J. Weinstein, Jose M. Ezquiaga

Monthly Notices of the Royal Astronomical Society, 2025

Targeted subthreshold search for strongly lensed gravitational-wave events

Alvin K. Y. Li, Rico K. L. Lo, Surabhi Sachdev, Juno C. L. Chan, E. T. Lin, Tjonnie G. F. Li, Alan J. Weinstein

Physical Review D, 2023

Search for Gravitational-lensing Signatures in the Full Third Observing Run of the LIGO-Virgo Network

LIGO-Virgo-KAGRA Collaboration

The Astrophysical Journal, 2024

Full publication list on researchmap

Selected Figures

TESLA-X workflow
TESLA-X workflow for constructing targeted template banks and population models.
Median localization area versus number of lensed images
Localization improvement from combining repeated lensed images.