Commensal discovery of four Fast Radio Bursts during Parkes Pulsar Timing Array observations

The Parkes Pulsar Timing Array(PPTA) project monitors two dozen millisecond pulsars(MSPs) in order to undertakea variety of fundamental physics experiments using the Parkes 64-m radio telescope. Since 2017 June, we have been undertaking commensalsearches for fast radio bursts(FRBs) during the MSP observations. Here, we report the discovery of four FRBs (171209, 180309, 180311, and 180714). The detected events include an FRB with the highest signal-to-noise ratio ever detected at the Parkes Observatory, which exhibits unusual spectral properties. All four FRBs are highly polarized. We discuss the future of commensalsearches for FRBs at Parkes.