Virgili, FJ, Mundell, CG, Pal'Shin, V, Guidorzi, C, Margutti, R, Melandri, A, Harrison, R, Kobayashi, S, Chornock, R, Henden, A, Updike, AC, Cenko, SB, Tanvir, NR, Steele, IA, Cucchiara, A, Gomboc, A, Levan, A, Cano, Z, Mottram, CJ, Clay, NR et al (2013) GRB 091024A and the Nature of Ultra-Long Gamma-Ray Bursts. Astrophysical Journal, 778 (1). ISSN 0004-637X
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Abstract
We present a broadband study of gamma-ray burst (GRB) 091024A within the context of other ultra-long-duration GRBs. An unusually long burst detected by Konus-Wind (KW), Swift, and Fermi, GRB 091024A has prompt emission episodes covering ~1300 s, accompanied by bright and highly structured optical emission captured by various rapid-response facilities, including the 2 m autonomous robotic Faulkes North and Liverpool Telescopes, KAIT, S-LOTIS, and the Sonoita Research Observatory. We also observed the burst with 8 and 10 m class telescopes and determine the redshift to be z = 1.0924 ± 0.0004. We find no correlation between the optical and γ-ray peaks and interpret the optical light curve as being of external origin, caused by the reverse and forward shock of a highly magnetized jet (RB ≈ 100-200). Low-level emission is detected throughout the near-background quiescent period between the first two emission episodes of the KW data, suggesting continued central-engine activity; we discuss the implications of this ongoing emission and its impact on the afterglow evolution and predictions. We summarize the varied sample of historical GRBs with exceptionally long durations in gamma-rays (gsim1000 s) and discuss the likelihood of these events being from a separate population; we suggest ultra-long GRBs represent the tail of the duration distribution of the long GRB population.
| Item Type: | Article | 
|---|---|
| Uncontrolled Keywords: | 0201 Astronomical And Space Sciences, 0305 Organic Chemistry, 0306 Physical Chemistry (Incl. Structural) | 
| Subjects: | Q Science > QB Astronomy Q Science > QC Physics Q Science > QD Chemistry | 
| Divisions: | Astrophysics Research Institute | 
| Publisher: | American Astronomical Society; IOP Publishing | 
| Related URLs: | |
| Date of acceptance: | 30 September 2013 | 
| Date of first compliant Open Access: | 28 November 2016 | 
| Date Deposited: | 28 Nov 2016 11:40 | 
| Last Modified: | 04 Sep 2021 12:13 | 
| DOI or ID number: | 10.1088/0004-637X/778/1/54 | 
| URI: | https://researchonline.ljmu.ac.uk/id/eprint/4880 | 
|  | View Item | 
 
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