TY - JOUR
T1 - Magnetic structures in gamma-ray burst jets probed by gamma-ray polarization
AU - Yonetoku, Daisuke
AU - Murakami, Toshio
AU - Gunji, Shuichi
AU - Mihara, Tatehiro
AU - Toma, Kenji
AU - Morihara, Yoshiyuki
AU - Takahashi, Takuya
AU - Wakashima, Yudai
AU - Yonemochi, Hajime
AU - Sakashita, Tomonori
AU - Toukairin, Noriyuki
AU - Fujimoto, Hirofumi
AU - Kodama, Yoshiki
PY - 2012/10/10
Y1 - 2012/10/10
N2 - 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.
AB - 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.
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U2 - 10.1088/2041-8205/758/1/L1
DO - 10.1088/2041-8205/758/1/L1
M3 - Article
AN - SCOPUS:84866667312
SN - 2041-8205
VL - 758
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L1
ER -