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Title: GRB 091024A and the nature of ultra-long gamma-ray bursts

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 (R{sub B} ≈ 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 (≳1000 s) and discuss the likelihood of these events being from a separate population; we suggest ultra-long GRBsmore » represent the tail of the duration distribution of the long GRB population.« less
Authors:
; ; ; ; ; ;  [1] ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] more »; « less
  1. Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom)
  2. Ioffe Physical Technical Institute, St. Petersburg 194021 (Russian Federation)
  3. Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, I-44122 Ferrara (Italy)
  4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  5. INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807 Merate (Italy)
  6. AAVSO, 49 Bay State Road, Cambridge, MA 02138 (United States)
  7. Department of Chemistry and Physics, Roger Williams University, Bristol, RI 02809 (United States)
  8. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
  9. Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)
  10. Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)
  11. Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia)
  12. Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)
  13. Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, 107 Reykjavik (Iceland)
Publication Date:
OSTI Identifier:
22342018
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 778; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AFTERGLOW; CORRELATIONS; COSMIC GAMMA BURSTS; COVERINGS; DIAGRAMS; DISTRIBUTION; EMISSION; EVOLUTION; FORECASTING; GAMMA RADIATION; RED SHIFT; TELESCOPES; VISIBLE RADIATION