Title: The First Matched-Filtering Search for Gravitational Waves from Eccentric Binary Black Holes

Speaker: Dr. Yifan Wang (Max Planck Institute for Gravitational Physics (Albert Einstein Institute))

Time: 14:00pm, August 18, 2025

Location: 3-402, PMO Xianlin Campus

Abstract: As gravitational wave astronomy has entered an era of routine detections, it becomes increasingly important to precisely measure the physical parameters of individual events and infer population properties. Among all properties, eccentricity is a key observable, suggesting that binaries form in a dense stellar environment through dynamical encounters. In this talk, I'll present a recent work (arXiv: 2508.05018) on the first matched-filtering search for gravitational waves with an effective-one-body waveform template modeled for eccentric binary black holes. The search region covers the mass range 5 to 200 solar masses, aligned spin amplitude -0.5 to 0.5, and eccentricity at 20 Hz up to 0.5. With a bank of ~80,0000 templates, we identified 28 events with a false alarm rate below once per 100 yr in the LIGO and Virgo's public O3 data; all of which were previously reported by the GWTC-3 and 4-OGC catalogs. Additional candidates with false alarm rates between once per 1 and 100 yr are also reported. Our results provide constraints on the event rate of eccentric binary black holes in the mass range [5, 30] solar masses. For a 30-30 solar mass binary black hole with eccentricity 0.5, the event rate is limited to less than 0.06 Gpc^-3 yr^-1; this marks an order of magnitude improvement for sensitive volume compared with the previous search with a minimally modeled algorithm without using templates. I will also discuss possible future directions for improving the search sensitivity with eccentricity. Speaker introduction: Dr. Yifan Wang is a postdoc in the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Potsdam, Germany. He obtained a Ph.D. degree from the Chinese University of Hong Kong and a Bachelor degree from the University of Science and Technology of China. His research interests encompass searching for gravitational waves from novel sources (including multimessenger sources) and testing general relativity (recently focusing on black hole ringdown) using data analysis tools.