The early X-ray emission from GRBs

P. T. O'Brien, R. Willingale, J. Osborne, M. R. Goad, K. L. Page, S. Vaughan, E. Rol, A. Beardmore, O. Godet, C. P. Hurkett, A. Wells, B. Zhang, S. Kobayashi, D. N. Burrows, J. A. Nousek, J. A. Kennea, A. Falcone, D. Grupe, N. Gehrels, S. BarthelmyJ. Cannizzo, J. Cummings, J. E. Hill, H. Krimm, G. Chincarini, G. Tagliaferri, S. Campana, A. Moretti, P. Giommi, M. Perri, V. Mangano, V. Laparola

Research output: Contribution to journalArticle

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Abstract

We present observations of the early X-ray emission for a sample of 40 gamma-ray bursts (GRBs) obtained using the Swift satellite, for which the narrow-field instruments were pointed at the burst within 10 minutes of the trigger. Using data from the Burst Alert Telescope and the X-Ray Telescope, we show that the X-ray light curve can be well described by an exponential that relaxes into a power law, often with flares superimposed. The transition time between the exponential and the power law provides a physically defined timescale for the burst duration. In most bursts, the power law breaks to a shallower decay within the first hour, and a late emission "hump" is observed, which can last for many hours. In other GRBs the hump is weak or absent. The observed variety in the shape of the early X-ray light curve can be explained as a combination of three components: prompt emission from the central engine, afterglow, and the late hump. In this scenario, afterglow emission begins during or soon after the burst, and the observed shape of the X-ray light curve depends on the relative strengths of the emission due to the central engine and that of the afterglow. There is a strong correlation such that those GRBs with stronger afterglow components have brighter early optical emission. The late emission hump can have a total fluence equivalent to that of the prompt phase. GRBs with the strongest late humps have weak or no X-ray flares.

Original languageEnglish (US)
Pages (from-to)1213-1237
Number of pages25
JournalAstrophysical Journal
Volume647
Issue number2 I
DOIs
StatePublished - Aug 20 2006

Fingerprint

gamma ray bursts
bursts
afterglows
light curve
x rays
power law
flares
engines
telescopes
engine
light emission
fluence
actuators
timescale
decay

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

O'Brien, P. T., Willingale, R., Osborne, J., Goad, M. R., Page, K. L., Vaughan, S., ... Laparola, V. (2006). The early X-ray emission from GRBs. Astrophysical Journal, 647(2 I), 1213-1237. https://doi.org/10.1086/505457
O'Brien, P. T. ; Willingale, R. ; Osborne, J. ; Goad, M. R. ; Page, K. L. ; Vaughan, S. ; Rol, E. ; Beardmore, A. ; Godet, O. ; Hurkett, C. P. ; Wells, A. ; Zhang, B. ; Kobayashi, S. ; Burrows, D. N. ; Nousek, J. A. ; Kennea, J. A. ; Falcone, A. ; Grupe, D. ; Gehrels, N. ; Barthelmy, S. ; Cannizzo, J. ; Cummings, J. ; Hill, J. E. ; Krimm, H. ; Chincarini, G. ; Tagliaferri, G. ; Campana, S. ; Moretti, A. ; Giommi, P. ; Perri, M. ; Mangano, V. ; Laparola, V. / The early X-ray emission from GRBs. In: Astrophysical Journal. 2006 ; Vol. 647, No. 2 I. pp. 1213-1237.
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abstract = "We present observations of the early X-ray emission for a sample of 40 gamma-ray bursts (GRBs) obtained using the Swift satellite, for which the narrow-field instruments were pointed at the burst within 10 minutes of the trigger. Using data from the Burst Alert Telescope and the X-Ray Telescope, we show that the X-ray light curve can be well described by an exponential that relaxes into a power law, often with flares superimposed. The transition time between the exponential and the power law provides a physically defined timescale for the burst duration. In most bursts, the power law breaks to a shallower decay within the first hour, and a late emission {"}hump{"} is observed, which can last for many hours. In other GRBs the hump is weak or absent. The observed variety in the shape of the early X-ray light curve can be explained as a combination of three components: prompt emission from the central engine, afterglow, and the late hump. In this scenario, afterglow emission begins during or soon after the burst, and the observed shape of the X-ray light curve depends on the relative strengths of the emission due to the central engine and that of the afterglow. There is a strong correlation such that those GRBs with stronger afterglow components have brighter early optical emission. The late emission hump can have a total fluence equivalent to that of the prompt phase. GRBs with the strongest late humps have weak or no X-ray flares.",
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O'Brien, PT, Willingale, R, Osborne, J, Goad, MR, Page, KL, Vaughan, S, Rol, E, Beardmore, A, Godet, O, Hurkett, CP, Wells, A, Zhang, B, Kobayashi, S, Burrows, DN, Nousek, JA, Kennea, JA, Falcone, A, Grupe, D, Gehrels, N, Barthelmy, S, Cannizzo, J, Cummings, J, Hill, JE, Krimm, H, Chincarini, G, Tagliaferri, G, Campana, S, Moretti, A, Giommi, P, Perri, M, Mangano, V & Laparola, V 2006, 'The early X-ray emission from GRBs', Astrophysical Journal, vol. 647, no. 2 I, pp. 1213-1237. https://doi.org/10.1086/505457

The early X-ray emission from GRBs. / O'Brien, P. T.; Willingale, R.; Osborne, J.; Goad, M. R.; Page, K. L.; Vaughan, S.; Rol, E.; Beardmore, A.; Godet, O.; Hurkett, C. P.; Wells, A.; Zhang, B.; Kobayashi, S.; Burrows, D. N.; Nousek, J. A.; Kennea, J. A.; Falcone, A.; Grupe, D.; Gehrels, N.; Barthelmy, S.; Cannizzo, J.; Cummings, J.; Hill, J. E.; Krimm, H.; Chincarini, G.; Tagliaferri, G.; Campana, S.; Moretti, A.; Giommi, P.; Perri, M.; Mangano, V.; Laparola, V.

In: Astrophysical Journal, Vol. 647, No. 2 I, 20.08.2006, p. 1213-1237.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The early X-ray emission from GRBs

AU - O'Brien, P. T.

AU - Willingale, R.

AU - Osborne, J.

AU - Goad, M. R.

AU - Page, K. L.

AU - Vaughan, S.

AU - Rol, E.

AU - Beardmore, A.

AU - Godet, O.

AU - Hurkett, C. P.

AU - Wells, A.

AU - Zhang, B.

AU - Kobayashi, S.

AU - Burrows, D. N.

AU - Nousek, J. A.

AU - Kennea, J. A.

AU - Falcone, A.

AU - Grupe, D.

AU - Gehrels, N.

AU - Barthelmy, S.

AU - Cannizzo, J.

AU - Cummings, J.

AU - Hill, J. E.

AU - Krimm, H.

AU - Chincarini, G.

AU - Tagliaferri, G.

AU - Campana, S.

AU - Moretti, A.

AU - Giommi, P.

AU - Perri, M.

AU - Mangano, V.

AU - Laparola, V.

PY - 2006/8/20

Y1 - 2006/8/20

N2 - We present observations of the early X-ray emission for a sample of 40 gamma-ray bursts (GRBs) obtained using the Swift satellite, for which the narrow-field instruments were pointed at the burst within 10 minutes of the trigger. Using data from the Burst Alert Telescope and the X-Ray Telescope, we show that the X-ray light curve can be well described by an exponential that relaxes into a power law, often with flares superimposed. The transition time between the exponential and the power law provides a physically defined timescale for the burst duration. In most bursts, the power law breaks to a shallower decay within the first hour, and a late emission "hump" is observed, which can last for many hours. In other GRBs the hump is weak or absent. The observed variety in the shape of the early X-ray light curve can be explained as a combination of three components: prompt emission from the central engine, afterglow, and the late hump. In this scenario, afterglow emission begins during or soon after the burst, and the observed shape of the X-ray light curve depends on the relative strengths of the emission due to the central engine and that of the afterglow. There is a strong correlation such that those GRBs with stronger afterglow components have brighter early optical emission. The late emission hump can have a total fluence equivalent to that of the prompt phase. GRBs with the strongest late humps have weak or no X-ray flares.

AB - We present observations of the early X-ray emission for a sample of 40 gamma-ray bursts (GRBs) obtained using the Swift satellite, for which the narrow-field instruments were pointed at the burst within 10 minutes of the trigger. Using data from the Burst Alert Telescope and the X-Ray Telescope, we show that the X-ray light curve can be well described by an exponential that relaxes into a power law, often with flares superimposed. The transition time between the exponential and the power law provides a physically defined timescale for the burst duration. In most bursts, the power law breaks to a shallower decay within the first hour, and a late emission "hump" is observed, which can last for many hours. In other GRBs the hump is weak or absent. The observed variety in the shape of the early X-ray light curve can be explained as a combination of three components: prompt emission from the central engine, afterglow, and the late hump. In this scenario, afterglow emission begins during or soon after the burst, and the observed shape of the X-ray light curve depends on the relative strengths of the emission due to the central engine and that of the afterglow. There is a strong correlation such that those GRBs with stronger afterglow components have brighter early optical emission. The late emission hump can have a total fluence equivalent to that of the prompt phase. GRBs with the strongest late humps have weak or no X-ray flares.

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O'Brien PT, Willingale R, Osborne J, Goad MR, Page KL, Vaughan S et al. The early X-ray emission from GRBs. Astrophysical Journal. 2006 Aug 20;647(2 I):1213-1237. https://doi.org/10.1086/505457