Magnetic structures in gamma-ray burst jets probed by gamma-ray polarization

Daisuke Yonetoku, Toshio Murakami, Shuichi Gunji, Tatehiro Mihara, Kenji Toma, Yoshiyuki Morihara, Takuya Takahashi, Yudai Wakashima, Hajime Yonemochi, Tomonori Sakashita, Noriyuki Toukairin, Hirofumi Fujimoto, Yoshiki Kodama

研究成果: Article査読

119 被引用数 (Scopus)


We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB110301A and GRB110721A, observed with the gamma-ray burst polarimeter (GAP) on borad the IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of Π = 70 ± 22% with statistical significance of 3.7σ for GRB110301A, and Π = 84 +16 - 28% with 3.3σ confidence level for GRB110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB100826A, which showed a significant change of polarization angle, as reported in Yonetoku etal. Synchrotron emission model can be consistent with the data of the three GRBs, while the photospheric quasi-thermal emission model is not favored. We suggest that magnetic field structures in the emission region are globally ordered fields advected from the central engine.

ジャーナルAstrophysical Journal Letters
出版ステータスPublished - 2012 10月 10

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学


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