Breaks and flares in long gamma-ray bursts from massive binaries

Ross P. Church, Melvyn B. Davies, Andrew J. Levan, Chunglee Kim

Research output: Contribution to journalConference articlepeer-review


We investigate the observational consequences of a binary model for long-duration gamma-ray bursts, in which the star producing the burst is in a close binary with a massive black-hole companion. This allows tidal interactions within the binary to keep the star spun up, which is necessary in order to form the accretion disc that powers the burst. We model the interaction of the supernova ejecta with the black hole companion and find that there are several robustly predicted features in the resulting accretion on to the disc that powers the gamma-ray burst. First, the accretion history shows a break at around 104 s. This is caused by the presence of the Roche lobe truncating the supply of material to the disc. Secondly, the draining of material that has built up in the disc causes a flare at a few times 104 s. The break time, flare time and total flare fluence show correlations, which owe their origin to a single parameter that determines the timescales present in the system, namely the orbital period of the binary system. Furthermore, we show that the properties of the flares are consistent with those of the late-time flares observed in X-ray light curves of some long-duration gamma-ray bursts.

Original languageEnglish
JournalProceedings of Science
StatePublished - 2012
Event2012 Gamma-Ray Bursts Conference, GRB 2012 - Munich, Germany
Duration: 7 May 201211 May 2012

Bibliographical note

Funding Information:
RPC is funded by a Marie-Curie Intra-European Fellowship, grant No. 252431, under the European Commission’s FP7 framework. CK acknowledges a Marie-Curie International Incom-

Funding Information:
ing Fellowship under the European Commission’s FP7 framework. This work was supported by the Swedish Research Council (grants 2008-4089 and 2011-3991). The calculations presented in this paper were carried out using computer hardware purchased with grants from the Royal Fys-iographic Society of Lund. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.

Publisher Copyright:
© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.


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