Extragalactic Radio Bursts

  • Lorimer burst
    The first extragalactic radio burst.
    Credit: Swinburne

    Extragalactic radio bursts are intense bursts of radio emission that have durations of milliseconds and exhibit the characteristic dispersion sweep of radio pulsars. Discovered in 2007 by Lorimer et al., the first extragalactic radio burst was actually observed some six years earlier, in archival data from a pulsar survey of the Magellanic clouds.

    Like giant pulses from radio pulsars like the Crab, the burst was extremely intense (30 Jy peak flux) and observed across a 288 MHz radio band. The dispersion measure of the radio burst was 375 pc cm-3 and was near the location of the Small Magellanic Cloud. The limited dynamic range of the instrumentation prohibited an exact measure of the flux, but it has been estimated that several 100 bursts could occur every day with a small probability of detection.

    The burst is still unique but its occurrence in 3 of the 13 beams of the Parkes multibeam receiver, classic dispersion sweep and evidence for scatter-broadening with the functional form expected make it rather convincing.

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