Testing the External-Shock Model of Gamma-Ray Bursts Using the Late-Time Simultaneous Optical and X-Ray Afterglows
抄録
type:text
We study the "normal" decay phase of the X- ray afterglows of gamma- ray bursts ( GRBs), which follows the shallow decay phase, using the events simultaneously observed in the R band. The classical external- shock model - in which neither the delayed energy injection nor time dependency of shock microphysics is considered shows that the decay indices of the X- ray and R- band light curves, alpha(x) and alpha(o), obey a certain relation, and that in particular, alpha(o) - alpha(x) should be larger than -1/4 unless the ambient density increases with the distance from the central engine. For our selected 14 samples, we have found that four events violate the limit at more than the 3 sigma level, so that a fraction of events are outliers of the classical external-shock model at the "normal" decay phase.
収録刊行物
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- The Astrophysical Journal Letters
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The Astrophysical Journal Letters 668 (2), L95-L98, 2007
American Astronomical Society
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詳細情報 詳細情報について
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- CRID
- 1050282812794646016
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- NII論文ID
- 120006385450
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- ISSN
- 0004637X
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- Web Site
- http://id.nii.ac.jp/1586/00012958/
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- 本文言語コード
- en
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- 資料種別
- journal article
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- データソース種別
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- IRDB
- CiNii Articles
- KAKEN