GRB 081008: From Burst to Afterglow and the Transition Phase in Between

F. Yuan, P. Schady, J.~L. Racusin, R. Willingale, T. Krühler, P.~T. O'Brien, J. Greiner, S.~R. Oates, E.~S. Rykoff, F. Aharonian, C.~W. Akerlof, M.~C.~B. Ashley, S.~D. Barthelmy, R. Filgas, H.~A. Flewelling, N. Gehrels, E. Göǧüș, T. Güver, D. Horns, Ü. Kiziloǧlu & 11 others H.~A. Krimm, T.~A. McKay, M.~E. Özel, A. Phillips, R.~M. Quimby, G. Rowell, W. Rujopakarn, B.~E. Schaefer, W.~T. Vestrand, J.~C. Wheeler, J. Wren

Research output: Contribution to journalArticle

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Abstract



We present a multi-wavelength study of GRB 081008, at redshift 1.967, by Swift, ROTSE-III, and Gamma-Ray Burst Optical/NearInfrared Detector. Compared to other Swift GRBs, GRB 081008 has a typical gamma-ray isotropic equivalent energy output (~1053 erg) during the prompt phase, and displayed two temporally separated clusters of pulses. The early X-ray emission seen by the Swift X-Ray Telescope was dominated by the softening tail of the prompt emission, producing multiple flares during and after the Swift Burst Alert Telescope detections. Optical observations that started shortly after the first active phase of gamma-ray emission showed two consecutive peaks. We interpret the first optical peak as the onset of the afterglow associated with the early burst activities. A second optical peak, coincident with the later gamma-ray pulses, imposes a small modification to the otherwise smooth light curve and thus suggests a minimal contribution from a probable internal component. We suggest the early optical variability may be from continuous energy injection into the forward shock front by later shells producing the second epoch of burst activities. These early observations thus provide a potential probe for the transition from the prompt phase to the afterglow phase. The later light curve of GRB 081008 displays a smooth steepening in all optical bands and X-ray. The temporal break is consistent with being achromatic at the observed wavelengths. Our broad energy coverage shortly after the break constrains a spectral break within optical. However, the evolution of the break frequency is not observed. We discuss the plausible interpretations of this behavior.
Original languageEnglish
Pages (from-to)870-880
Number of pages11
JournalAstrophysical Journal
Volume711
Issue number2
DOIs
Publication statusPublished - 10 Mar 2010

Keywords

  • gamma-ray burst: individual: GRB 081008, Astrophysics - High Energy Astrophysical Phenomena

Cite this

Yuan, F., Schady, P., Racusin, J. L., Willingale, R., Krühler, T., O'Brien, P. T., ... Wren, J. (2010). GRB 081008: From Burst to Afterglow and the Transition Phase in Between. Astrophysical Journal, 711(2), 870-880. https://doi.org/10.1088/0004-637X/711/2/870

GRB 081008: From Burst to Afterglow and the Transition Phase in Between. / Yuan, F.; Schady, P.; Racusin, J.~L.; Willingale, R.; Krühler, T.; O'Brien, P.~T.; Greiner, J.; Oates, S.~R.; Rykoff, E.~S.; Aharonian, F.; Akerlof, C.~W.; Ashley, M.~C.~B.; Barthelmy, S.~D.; Filgas, R.; Flewelling, H.~A.; Gehrels, N.; Göǧüș, E.; Güver, T.; Horns, D.; Kiziloǧlu, Ü.; Krimm, H.~A.; McKay, T.~A.; Özel, M.~E.; Phillips, A.; Quimby, R.~M.; Rowell, G.; Rujopakarn, W.; Schaefer, B.~E.; Vestrand, W.~T.; Wheeler, J.~C.; Wren, J.

In: Astrophysical Journal, Vol. 711, No. 2, 10.03.2010, p. 870-880.

Research output: Contribution to journalArticle

Yuan, F, Schady, P, Racusin, JL, Willingale, R, Krühler, T, O'Brien, PT, Greiner, J, Oates, SR, Rykoff, ES, Aharonian, F, Akerlof, CW, Ashley, MCB, Barthelmy, SD, Filgas, R, Flewelling, HA, Gehrels, N, Göǧüș, E, Güver, T, Horns, D, Kiziloǧlu, Ü, Krimm, HA, McKay, TA, Özel, ME, Phillips, A, Quimby, RM, Rowell, G, Rujopakarn, W, Schaefer, BE, Vestrand, WT, Wheeler, JC & Wren, J 2010, 'GRB 081008: From Burst to Afterglow and the Transition Phase in Between', Astrophysical Journal, vol. 711, no. 2, pp. 870-880. https://doi.org/10.1088/0004-637X/711/2/870
Yuan, F. ; Schady, P. ; Racusin, J.~L. ; Willingale, R. ; Krühler, T. ; O'Brien, P.~T. ; Greiner, J. ; Oates, S.~R. ; Rykoff, E.~S. ; Aharonian, F. ; Akerlof, C.~W. ; Ashley, M.~C.~B. ; Barthelmy, S.~D. ; Filgas, R. ; Flewelling, H.~A. ; Gehrels, N. ; Göǧüș, E. ; Güver, T. ; Horns, D. ; Kiziloǧlu, Ü. ; Krimm, H.~A. ; McKay, T.~A. ; Özel, M.~E. ; Phillips, A. ; Quimby, R.~M. ; Rowell, G. ; Rujopakarn, W. ; Schaefer, B.~E. ; Vestrand, W.~T. ; Wheeler, J.~C. ; Wren, J. / GRB 081008: From Burst to Afterglow and the Transition Phase in Between. In: Astrophysical Journal. 2010 ; Vol. 711, No. 2. pp. 870-880.
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abstract = "We present a multi-wavelength study of GRB 081008, at redshift 1.967, by Swift, ROTSE-III, and Gamma-Ray Burst Optical/NearInfrared Detector. Compared to other Swift GRBs, GRB 081008 has a typical gamma-ray isotropic equivalent energy output (~1053 erg) during the prompt phase, and displayed two temporally separated clusters of pulses. The early X-ray emission seen by the Swift X-Ray Telescope was dominated by the softening tail of the prompt emission, producing multiple flares during and after the Swift Burst Alert Telescope detections. Optical observations that started shortly after the first active phase of gamma-ray emission showed two consecutive peaks. We interpret the first optical peak as the onset of the afterglow associated with the early burst activities. A second optical peak, coincident with the later gamma-ray pulses, imposes a small modification to the otherwise smooth light curve and thus suggests a minimal contribution from a probable internal component. We suggest the early optical variability may be from continuous energy injection into the forward shock front by later shells producing the second epoch of burst activities. These early observations thus provide a potential probe for the transition from the prompt phase to the afterglow phase. The later light curve of GRB 081008 displays a smooth steepening in all optical bands and X-ray. The temporal break is consistent with being achromatic at the observed wavelengths. Our broad energy coverage shortly after the break constrains a spectral break within optical. However, the evolution of the break frequency is not observed. We discuss the plausible interpretations of this behavior.",
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T1 - GRB 081008: From Burst to Afterglow and the Transition Phase in Between

AU - Yuan, F.

AU - Schady, P.

AU - Racusin, J.~L.

AU - Willingale, R.

AU - Krühler, T.

AU - O'Brien, P.~T.

AU - Greiner, J.

AU - Oates, S.~R.

AU - Rykoff, E.~S.

AU - Aharonian, F.

AU - Akerlof, C.~W.

AU - Ashley, M.~C.~B.

AU - Barthelmy, S.~D.

AU - Filgas, R.

AU - Flewelling, H.~A.

AU - Gehrels, N.

AU - Göǧüș, E.

AU - Güver, T.

AU - Horns, D.

AU - Kiziloǧlu, Ü.

AU - Krimm, H.~A.

AU - McKay, T.~A.

AU - Özel, M.~E.

AU - Phillips, A.

AU - Quimby, R.~M.

AU - Rowell, G.

AU - Rujopakarn, W.

AU - Schaefer, B.~E.

AU - Vestrand, W.~T.

AU - Wheeler, J.~C.

AU - Wren, J.

PY - 2010/3/10

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N2 - We present a multi-wavelength study of GRB 081008, at redshift 1.967, by Swift, ROTSE-III, and Gamma-Ray Burst Optical/NearInfrared Detector. Compared to other Swift GRBs, GRB 081008 has a typical gamma-ray isotropic equivalent energy output (~1053 erg) during the prompt phase, and displayed two temporally separated clusters of pulses. The early X-ray emission seen by the Swift X-Ray Telescope was dominated by the softening tail of the prompt emission, producing multiple flares during and after the Swift Burst Alert Telescope detections. Optical observations that started shortly after the first active phase of gamma-ray emission showed two consecutive peaks. We interpret the first optical peak as the onset of the afterglow associated with the early burst activities. A second optical peak, coincident with the later gamma-ray pulses, imposes a small modification to the otherwise smooth light curve and thus suggests a minimal contribution from a probable internal component. We suggest the early optical variability may be from continuous energy injection into the forward shock front by later shells producing the second epoch of burst activities. These early observations thus provide a potential probe for the transition from the prompt phase to the afterglow phase. The later light curve of GRB 081008 displays a smooth steepening in all optical bands and X-ray. The temporal break is consistent with being achromatic at the observed wavelengths. Our broad energy coverage shortly after the break constrains a spectral break within optical. However, the evolution of the break frequency is not observed. We discuss the plausible interpretations of this behavior.

AB - We present a multi-wavelength study of GRB 081008, at redshift 1.967, by Swift, ROTSE-III, and Gamma-Ray Burst Optical/NearInfrared Detector. Compared to other Swift GRBs, GRB 081008 has a typical gamma-ray isotropic equivalent energy output (~1053 erg) during the prompt phase, and displayed two temporally separated clusters of pulses. The early X-ray emission seen by the Swift X-Ray Telescope was dominated by the softening tail of the prompt emission, producing multiple flares during and after the Swift Burst Alert Telescope detections. Optical observations that started shortly after the first active phase of gamma-ray emission showed two consecutive peaks. We interpret the first optical peak as the onset of the afterglow associated with the early burst activities. A second optical peak, coincident with the later gamma-ray pulses, imposes a small modification to the otherwise smooth light curve and thus suggests a minimal contribution from a probable internal component. We suggest the early optical variability may be from continuous energy injection into the forward shock front by later shells producing the second epoch of burst activities. These early observations thus provide a potential probe for the transition from the prompt phase to the afterglow phase. The later light curve of GRB 081008 displays a smooth steepening in all optical bands and X-ray. The temporal break is consistent with being achromatic at the observed wavelengths. Our broad energy coverage shortly after the break constrains a spectral break within optical. However, the evolution of the break frequency is not observed. We discuss the plausible interpretations of this behavior.

KW - gamma-ray burst: individual: GRB 081008, Astrophysics - High Energy Astrophysical Phenomena

U2 - 10.1088/0004-637X/711/2/870

DO - 10.1088/0004-637X/711/2/870

M3 - Article

VL - 711

SP - 870

EP - 880

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

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