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arXiv · 1310.4944

Are Ultra-long Gamma-Ray Bursts different?

Michel Boer·Bruce Gendre·Giulia Stratta
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Abstract

The discovery of a number of gamma-ray bursts with duration exceeding 1,000 seconds, in particular the exceptional case of GRB 111209A with a duration of about 25,000 seconds, has opened the question on whether these bursts form a new class of sources, the so called {\em ultra-long} GRBs, or if they are rather the tail of the distribution of the standard long GRB duration. In this Letter, using the long GRB sample detected by {\em Swift}, we investigate on the statistical properties of ultra-long GRBs and compare them with the overall long burst population. We discuss also on the differences observed in their spectral properties. We find that ultra-long GRBs are statistically different from the standard long GRBs with typical burst duration less than 100-500 seconds, for which a Wolf Rayet star progenitor is usually invoked. We interpret this result as an indication that an alternative scenario has to be found in order to explain the ultra-long GRB extreme energetics, as well as the mass reservoir and its size that can feed the central engine for such a long time.

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Michel Boer, Bruce Gendre, Giulia Stratta. 2013-10-18. Are Ultra-long Gamma-Ray Bursts different?. https://doi.org/10.1088/0004-637x/800/1/16

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