Shanghai Astronomical Observatory Astrophysics Colloquium

Title：To the "Time Frontier" with the Commensal Radio Astronomy FAST Survey (CRAFTS)

Speaker：Dr. Di Li (Tsinghua University)

Time：3:00 pm March 19th (Thursday)

Tencent Meeting：46822606747 password: 6360

Location: Lecture Hall, 3rd floor

Abstract：

The Parkes multi-beam system transformed single-dish radio astronomy, delivering the largest haul of new pulsars, definitive HI galaxy catalogues, and the standard HI maps of the Southern sky. These landmark surveys had to be conducted separately, due to the conflicting observation requirements. We invented the high-cadence CAL technique, in which the calibration signal is injected at the sampling rate and facilitate, for the first time, truly commensal pulsar and spectral-line surveys. Implemented on FAST with drift-scan mode, the Commensal Radio Astronomy FAST Survey (CRAFTS) has discovered more than 230 pulsars and 10 FRBs, and released over 5,000 square degrees of calibrated HI images. I will report several science highlights from CRAFTS, including spatially resolved mapping of low-energy cosmic rays via HINSA, origin of galactic turbulence in M31, and our hypothesis for a unified origin of all fast radio bursts. CRAFTS' high cadence sampling of the radio sky also give rise to the concept of the "time frontier". I coined this term to represent the quantum foundation of the Universe that is to be revealed by exploring the extreme transients.

CV：

Dr. Li, radio astronomer, is a Chair Professor of Tsinghua University and the former Chief Scientist of FAST. He pioneered several observing and data analysis techniques, including HI Narrow Self-Absorption (HINSA) and high-cadence CAL. These techniques led to major discoveries and new surveys. including the Commensal Radio Astronomy FasT Survey (CRAFTS), precise measurement of interstellar magnetic field, and the first persistently active fast radio bursts (FRB), etc. He has published more than 400 peer-reviewed journal articles with more than 13000 citations. He won the 2022 Distinguished Achievement Award of the Chinese Academy of Sciences (CAS); the 3rd National Innovation Award from the Chinese government; and the 17^th Marcel Grossmann Award for ”numerous innovations in characterizing the dynamic universe”.

 Koushare link to the recorded presentation