Fast Radio Burst Counterparts: Multi-wavelength Clues to their Nature and Origin

by Prof. Wenfei Yu(余文飞) (SHAO)

Wednesday 23 Sept 2026, 14:00 → 15:00 Asia/Shanghai

Tsung-Dao Lee Institute/S4F-SW - Open Area (Tsung-Dao Lee Institute)

Host: Dong Lai
Join Tencent Meeting：https://meeting.tencent.com/dm/INupzDcjoHq5
Meeting ID: 633652577 (no password）

Abstract:
Fast Radio Bursts (FRBs) are bright, short (typically millisecond-duration), and narrow-band (typically a few hundred MHz) radio bursts of unknown cosmic origin. The discovery of astrophysical counterparts to FRBs would allow direct probes of the immediate environment and even the birth site of the burst engine. Among the more than 1000 distinct FRB sources detected to date, only a small fraction have been identified as repeaters. These repeaters exhibit distinct “active” and “quiescent” episodes. During highly active periods, they provide the best opportunities for sub-arcsecond localization to identify their host galaxies and potential multi-wavelength counterparts. Recent observations have only been able to confirm 4-5 compact radio continuum counterparts associated with repeating FRBs. Our team discovered two of these—the radio continuum counterparts to FRB 20190520B and FRB 20240114A—through interferometric observations. In this talk, I will focus on the hyperactive source FRB 20240114A and present unique temporal, spectral, and evolutionary evidence for an explosive transient, likely associated with a newborn compact object. Specifically, it is the first FRB radio continuum counterpart observed to behave as a slow radio transient, similar to engine-powered radio supernovae. It is also the first FRB radio counterpart convincingly detected with evolving synchrotron self-absorption (SSA) spectra, constraining the size and magnetic field of the radio source to values more than an order of magnitude more extreme than those of any other known FRB counterpart. Our tentative detection of sub-minute gamma-ray flares from the FRB source, combined with the detection of evolving radio SSA spectra in the radio counterpart, suggests a promising strategy for future searches for newborn FRB sources to reveal the origin of FRBs.

Biography:
Prof. Wenfei Yu began his graduate studies in black hole accretion theory at Central China Normal University, where he earned his MSc, before obtaining his Ph.D. in particle physics from the Institute of High Energy Physics (IHEP), Chinese Academy of Sciences. His doctoral thesis earned the National Excellent Ph.D. Thesis Award in 2000. He subsequently conducted postdoctoral research in X-ray astronomy and relativistic astrophysics at the Anton Pannekoek Institute for Astronomy (University of Amsterdam) and the Physics Department of the University of Illinois at Urbana-Champaign. In late 2006, he established the Observational High-Energy Astrophysics Group at the Shanghai Astronomical Observatory. Since then, his group has extended observational studies from X-ray/gamma-ray wavelengths to the optical and the radio wavelengths, accompanied by the scientific advance into time-domain astronomy, by conducting competitive, simultaneous and/or  coordinated space- and ground-based multi-wavelength observations of high-energy and relativistic transients, including black hole transients and fast radio bursts (FRBs). His expertise centers on multi-wavelength timing observations of compact objects and space-borne/ground-based follow-up observations of high-energy and radio transients, with a focus and interest on the physics of compact objects under extreme conditions usually probed on time scales as short as milliseconds. Recent achievements by his group and collaborators include: (1) the discovery of two compact radio counterparts to FRBs (out of approximately four to five confirmed compact radio counterparts among more than 1,000 distinct burst sources) exhibiting continuum emission; and (2) the detection of the most relativistic jet ejections ever observed from Galactic microquasars, with the Lorentz factor exceeding about 8. In addition to frontier research, he has also played major roles in science working groups for several major space- and ground-based astronomical missions or facilities, including the ultra-dense matter physics of the enhanced X-ray Timing and Polarimetry (eXTP) mission, the Key Science Project on FRBs for the Five-hundred-meter Aperture Spherical radio Telescope (FAST), and the radio transient science of the Square Kilometre Array (SKA). To promote international collaboration in space astronomy, he currently serves as Vice-Chair of COSPAR Scientific Commission E: Research in Astrophysics from Space.