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Activity Number:
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358
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Type:
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Contributed
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Date/Time:
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Wednesday, August 14, 2002 : 2:00 PM to 3:50 PM
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Sponsor:
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Section on Physical & Engineering Sciences*
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| Abstract - #301044 |
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Title:
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Profile Statistics of Gamma Ray Burst
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Author(s):
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Donald Cotten*+ and Tak Cheung
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Affiliation(s):
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City University of New York-Queensborough Community College and City University of New York-Queensborough Community College
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Address:
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222-05 56th Ave, Bayside, New York, 11364, USA
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Keywords:
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diffusion profile ; random walk ; boundary condition
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Abstract:
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Some gamma ray burst charts collected by the BATSE satellite contain temporal burst profiles that are characterized by fast rise, exponential decay (FRED) features. Bursts have been ascribed to shock wave collisions. In contrast, solar flare charts collected by the recently launched RHESSI satellite contain Lorentzian-like profiles at gamma energy. Similar FRED features are also observed in light diffusion through a turbid medium using a laser pulse/burst. This study attempts to use the gamma ray burst temporal profile to extract the scattering parameters of the surrounding medium. Monte Carlo simulation of photon random walk through a turbid medium with an appropriate input pulse/burst is used to fit observed gamma ray burst profiles. This diffusion-broadened profile model appears to be consistent with the recent finding that the medium surrounding the shock waves contains heavy elements. Pre-burst temporal profile can be interpreted using a Poisson random walk for energetic particles, where gamma photons were allowed to escape as the particles exited the turbid medium boundary. The parameters thus extracted predict and supplement the post-burst afterglow data.
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