Testing the External-Shock Model of Gamma-Ray Bursts Using the Late-Time Simultaneous Optical and X-Ray Afterglows

• 浦田, 裕次

• Yamazaki, Ryo

• Sakamoto, Takanori

• Huang, Kuiyun

• Zheng, Weikang

• Sato, Goro

• Aoki, Tsutomu

• Deng, Jinsong

• Ioka, Kunihito

• Ip, WingHuen

• Kawabata, Koji S.

• Lee, YiHsi

• Xin, Liping

• Mito, Liping

• Miyata, Takashi

• Nakada, Yoshikazu

• Ohsugi, Takashi

• Qiu, Yulei

• Soyano, Takao

• Tarusawa, Kenichi

• 田代, 信

• Uemura, Makoto

• Wei, Jianyan

• Yamashita, Takuya

Abstract

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.

Journal

• The Astrophysical Journal Letters

  The Astrophysical Journal Letters 668 (2), L95-L98, 2007

  American Astronomical Society

Keywords

• gamma rays : bursts
• gamma rays : observations

Details

• CRID: 1050282812794646016
• NII Article ID: 120006385450
• ISSN: 0004637X
• Web Site: http://id.nii.ac.jp/1586/00012958/
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles
  • KAKEN