lundi 8 avril 2024, par Prof. Di LI (Chief Scientist of FAST, National Astronomical Observatories of Chinese Academy of Sciences)
Vendredi 12 avril 2024 de 11:00 à 12:00 , Lieu : Salle de confĂ©rence du bâtiment 17
With FAST, the largest single-dish telescope ever built , we have designed the Commensal Radio Astronomy FAST Survey (CRAFTS), which realizes, for the first time at any major facility, simultaneous data recording of pulsar search, HI imaging, HI galaxies, and transients (FRB and SETI). CRAFTS has discovered 200 pulsars, 10 FRBs including the only persistently active repeater FRB 20190520B, and 5000 d^2 HI images with 1% calibration consistency, 5-10 times better than what is available from Arecibo. Based on CRAFTS, we derived a FRB event rate 120K per day per 4pi. We find universal frequency-dependent depolarization among repeating FRBs, which can be well fitted by multi-path scattering and a single free parameter sigma_RM that described the complexity of the magnetized environments of FRBs. We have published in 2021 the first complete burst rate energy distribution toward any FRB, which is clearly bimodal. Such bimodality was later borne out in the subsequent monitoring of all the active repeaters. Recently, 10% drop of FRB 121102’s DM on a decade time scale, is being robustly detected. I am proposing an evolutionary picture of FRBs, which aims to unify not only repeating FRBs, but most if not all non-repeaters.
