A survey of FRB fields: Limits on repeatability

Several theories exist to explain the source of the bright, millisecond duration pulses known as fast radio bursts (FRBs). If the progenitors of FRBs are non-cataclysmic, such as giant pulses from pulsars, pulsar-planet binaries, or magnetar flares, FRB emission may be seen to repeat. We have undertaken a survey of the fields of eight known FRBs from the High Time Resolution Universe survey to search for repeating pulses. Although no repeat pulses were detected the survey yielded the detection of a new FRB, described in Petroff et al. (2015a). From our observations we rule out periodic repeating sources with periods P <= 8.6 h and rule out sources with periods 8.6 < P < 21 h at the 90 per cent confidence level. At P >= 21 h our limits fall off as similar to 1/P. Dedicated and persistent observations of FRB source fields are needed to rule out repetition on longer time-scales, a task well-suited to next generation wide-field transient detectors.