Can we quickly flag Ultra-long Gamma-Ray Bursts?

• Main Authors: Gendre, B, Joyce, Q. T, Orange, N. B, Stratta, G, Atteia, J. L, Boer, M
• Format: Journal Article
• Language: English
• Published: 09-04-2019
• Subjects: Physics - High Energy Astrophysical Phenomena
• DOI: 10.48550/arxiv.1904.04550

MNRAS, Vol 486, pp2471-2476 (2019) Ultra-long Gamma-Ray Bursts are a class of high energy transients lasting
several hours. Their exact nature is still elusive, and several models have
been proposed to explain them. Because of the limited coverage of wide field
gamma-ray detectors, the study of their prompt phase with sensitive
narrow-field X-ray instruments could help in understanding the origin of
ultra-long GRBs. However, the observers face a true problem in rapidly
activating follow-up observations, due to the challenging identification of an
ultra-long GRB before the end of the prompt phase. We present here a comparison
of the prompt properties available after a few tens of minutes of a sample of
ultra-long GRBs and normal long GRBs, looking for prior indicators of the long
duration. We find that there is no such clear prior indicator of the duration
of the burst. We also found that statistically, a burst lasting at least 10 and
20 minutes has respectively 28% and 50% probability to be an ultralong event.
These findings point towards a common central engine for normal long and
ultra-long GRBs, with the collapsar model privileged.