Статья

The Early X‐Ray Emission from GRBs

P. T. O’BrienDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKR. WillingaleDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKJ. OsborneDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKM. R. GoadDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKK. L. PageDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKS. VaughanDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKE. RolDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKA. BeardmoreDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKO. GodetDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKC. P. HurkettDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKA. WellsDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKB. ZhangDepartment of Physics, University of Nevada, Las Vegas, NV 89154S. KobayashiAstrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Birkenhead CH41 1LD, UKD. N. BurrowsDepartment of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802J. A. NousekDepartment of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802J. A. KenneaDepartment of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802A. FalconeDepartment of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802D. GrupeDepartment of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802N. GehrelsNASA/Goddard Space Flight Center, Greenbelt, MD 20771S. BarthelmyNASA/Goddard Space Flight Center, Greenbelt, MD 20771J. CannizzoJoint Center for Astrophysics, University of Maryland, Baltimore County, Baltimore, MD 21250J. CummingsNASA/Goddard Space Flight Center, Greenbelt, MD 20771J. E. HillNASA/Goddard Space Flight Center, Greenbelt, MD 20771H. KrimmNASA/Goddard Space Flight Center, Greenbelt, MD 20771G. ChincariniINAF—Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (LC), ItalyG. TagliaferriINAF—Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (LC), ItalyS. CampanaINAF—Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (LC), ItalyA. MorettiINAF—Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (LC), ItalyP. GiommiM. PerriV. ManganoINAF—Istituto di Astrofisica Spaziale e Fisica Cosmica Sezione di Palermo, Via U. La Malfa 153, I-90146 Palermo, ItalyV. LaParolaINAF—Istituto di Astrofisica Spaziale e Fisica Cosmica Sezione di Palermo, Via U. La Malfa 153, I-90146 Palermo, Italy

2006en

ABI

Аннотация

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 and X-Ray Telescopes, 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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Идентификаторы

DOI: 10.1086/505457

Цитирования и источники

Цитирований: 2Использованных источников: 0

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