The Commensal Radio Astronomy FAST Survey (CRAFTS) and a finding chart for SKA.

Image credit: https://astro.tsinghua.edu.cn

The Parkes multi-beam system transformed single-dish radio astronomy, delivering the largest haul of new pulsars from any instrument, 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 between those of pulsars and HI. The electronic calibration (CAL) signal required for precise HI gain calibration contaminates pulsar power spectra and therefore must traditionally be switched off during pulsar searches. 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 simultaneous 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 the origin of repeating fast radio bursts.