Do gamma-ray bursts produce Lorimer bursts?

Sep 4, 2012

Since Lorimer et al. (2007) reported the detection of a single short and bright radio burst that could be traced back to extragalactic origin, astronomers have tried to come up with plausible models to explain the observation and have conducted surveys to detect more of these peculiar signals. While we are still lacking a good model, CAASTRO’s ex-PhD student and now CSIRO Bolton Fellow Keith Bannister and his CAASTRO and CSIRO co-workers might have found the mechanism that produces the phenomenon.

In their recent 2012 paper “Limits on Prompt, Dispersed Radio Pulses from Gamma-Ray Bursts” (The Astrophysical Journal 757-38), they present a thorough examination of nine months of radio data collected immediately after the detection of gamma-ray bursts by the Swift satellite. Out of nine observed gamma-ray bursts, Bannister et al. found that two produced single-radio bursts that satisfied their stringent analysis, taking into account the possible contamination through radio frequency interference. Unless these observations can be repeated with a different telescope, radio interference remains difficult to rule out.

Having drilled further down into the data, the research team could conclude that the pulses are not due to random noise fluctuations at 95% confidence (assuming Gaussian noise) and 97% confidence (running a null trial of randomised channels in their data processing).

Publication details:

K.W. Bannister, T. Murphy, B.M. Gaensler, J.E. Reynolds in ApJ 757:

Limits on Prompt, Dispersed Radio Pulses from Gamma-Ray Bursts