Hostname: page-component-848d4c4894-5nwft Total loading time: 0 Render date: 2024-04-30T20:58:19.052Z Has data issue: false hasContentIssue false
  • English
  • Français

Study of emission mechanism of GRBs probed by the gamma-ray polarization with IKAROS-GAP

Published online by Cambridge University Press:  05 September 2012

Daisuke Yonetoku ,
Toshio Murakami ,
Tomonori Sakashita ,
Yoshiyuki Morihara ,
Shuichi Gunji ,
Tatehiro Mihara  and
Kenji Toma
Daisuke Yonetoku
Affiliation:
College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, email: (DY) yonetoku@astro.s.kanazawa-u.ac.jp
Toshio Murakami
Affiliation:
College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, email: (DY) yonetoku@astro.s.kanazawa-u.ac.jp
Tomonori Sakashita
Affiliation:
College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, email: (DY) yonetoku@astro.s.kanazawa-u.ac.jp
Yoshiyuki Morihara
Affiliation:
College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, email: (DY) yonetoku@astro.s.kanazawa-u.ac.jp
Shuichi Gunji
Affiliation:
Department of Physics, Faculty of Science, Yamagata University, 1-4-12, Koshirakawa, Yamagata, Yamagata 990-8560, Japan
Tatehiro Mihara
Affiliation:
Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198, Japan
Kenji Toma
Affiliation:
Department of Earth and Space Science, Osaka University, Toyonaka 560-0043, Japan
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We report a polarization measurement in prompt γ-ray emission of GRB 100826A with the Gamma-Ray Burst Polarimeter (GAP) aboard the small solar power sail demonstrator IKAROS. We detected a firm change of polarization angle (PA) during the prompt emission with 99.9% (3.5 σ) confidence level, and an average polarization degree (Π) of 27 ± 11% with 99.4% (2.9 σ) confidence level. Here the quoted errors are given at 1 σ confidence level for two parameters of interest. Non-axisymmetric (e.g., patchy) structures of the magnetic fields and/or brightness inside the relativistic jet are therefore required within the observable angular scale of ~ Γ−1. Our observation strongly indicates that the polarization measurement is a powerful tool to constrain the GRB production mechanism, and more theoretical works are needed to discuss the data in more details.

Keywords

Gamma-Ray Burstspolarizationemission mechanism
Type
Poster Papers
Information
Proceedings of the International Astronomical Union , Volume 7 , Symposium S279: Death of Massive Stars: Supernovae and Gamma-Ray Bursts , April 2011 , pp. 425 - 426
Copyright
Copyright © International Astronomical Union 2012

References

Costa, E. et al. , 1997, Nature 387 783–785CrossRefGoogle Scholar
Lazzati, D. et al. , 2006, New Journal of Physics, 8, 131Google Scholar
Mészáros, P. 2006, Rep. Prog. Phys., 69, 2259Google Scholar
Toma, K., Sakamoto, T., Zhang, B., et al. 2009, ApJ, 698, 1042Google Scholar
Yonetoku, D., Murakami, T., Gunji, S., Mihara, T., et al. , 2011, PASJ, 63, 3CrossRefGoogle Scholar
Yonetoku, D., Murakami, T., Gunji, S., Mihara, T., Toma, K., et al. , 2011, ApJ, 743, L30CrossRefGoogle Scholar