GRB 091208B: FIRST DETECTION OF THE OPTICAL POLARIZATION IN EARLY FORWARD SHOCK EMISSION OF A GAMMA-RAY BURST AFTERGLOW

被引：47

作者：

Uehara, T. ^{[1
]}

Toma, K. ^{[2
]}

Kawabata, K. S. ^{[3
]}

Chiyonobu, S. ^{[1
]}

Fukazawa, Y. ^{[1
]}

Ikejiri, Y. ^{[1
]}

Inoue, T. ^{[4
]}

Itoh, R. ^{[1
]}

Komatsu, T. ^{[1
]}

Miyamoto, H. ^{[1
]}

Mizuno, T. ^{[3
]}

Nagae, O. ^{[1
]}

Nakaya, H. ^{[5
]}

Ohsugi, T. ^{[3
]}

Sakimoto, K. ^{[1
]}

Sasada, M. ^{[1
]}

Tanaka, H. ^{[1
]}

Uemura, M. ^{[3
]}

Yamanaka, M. ^{[1
,3
]}

Yamashita, T. ^{[4
]}

Yamazaki, R. ^{[4
]}

Yoshida, M. ^{[3
]}

机构：

[1] Hiroshima Univ, Dept Phys Sci, Higashihiroshima 7398526, Japan

[2] Osaka Univ, Dept Earth & Space Sci, Toyonaka, Osaka 5600043, Japan

[3] Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Higashihiroshima, Hiroshima 7398526, Japan

[4] Aoyama Gakuin Univ, Dept Math & Phys, Chuou Ku, Sagamihara, Kanagawa 2525258, Japan

[5] Natl Inst Nat Sci, Natl Astron Observ Japan, Mitaka, Tokyo 1818588, Japan

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2012年 / 752卷 / 01期

关键词：

gamma-ray burst: individual (GRB 091208B); magnetic fields; polarization; shock waves; PROMPT EMISSION; LIGHT CURVES; LINEAR-POLARIZATION; RELATIVISTIC SHOCK; POLARIMETRY; DEPENDENCE; TURBULENCE; PHASE; MODEL;

D O I：

10.1088/2041-8205/752/1/L6

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report that the optical polarization in the afterglow of GRB 091208B is measured at t = 149-706 s after the burst trigger, and the polarization degree is P = 10.4% +/- 2.5%. The optical light curve at this time shows a power-law decay with index -0.75 +/- 0.02, which is interpreted as the forward shock synchrotron emission, and thus this is the first detection of the early-time optical polarization in the forward shock (rather than that in the reverse shock reported by Steele et al.). This detection disfavors the afterglow model in which the magnetic fields in the emission region are random on the plasma skin depth scales, such as those amplified by the plasma instabilities, e.g., Weibel instability. We suggest that the fields are amplified by the magnetohydrodynamic instabilities, which would be tested by future observations of the temporal changes of the polarization degrees and angles for other bursts.

引用

页数：5

共 36 条

[1]

Covino S, 2004, ASTR SOC P, V312, P169

[2] H I IN THE GALAXY [J].

DICKEY, JM ;

LOCKMAN, FJ .

ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1990, 28 :215-261

[3] Late prompt emission in gamma-ray bursts? [J].

Ghisellini, G. ;

Ghirlanda, G. ;

Nava, L. ;

Firmani, C. .

ASTROPHYSICAL JOURNAL, 2007, 658 (02) :L75-L78

[4] Polarization light curves and position angle variation of beamed gamma-ray bursts [J].

Ghisellini, G ;

Lazzati, D .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1999, 309 (01) :L7-L11

[5] Linear polarization in gamma-ray bursts:: The case for an ordered magnetic field [J].

Granot, J ;

Königl, A .

ASTROPHYSICAL JOURNAL, 2003, 594 (02) :L83-L87

[6] The shape of spectral breaks in gamma-ray burst afterglows [J].

Granot, J ;

Sari, R .

ASTROPHYSICAL JOURNAL, 2002, 568 (02) :820-829

[7] Gamma-ray burst afterglow: Polarization and analytic light curves [J].

Gruzinov, A ;

Waxman, E .

ASTROPHYSICAL JOURNAL, 1999, 511 (02) :852-861

[8] THREE-DIMENSIONAL SIMULATIONS OF MAGNETOHYDRODYNAMIC TURBULENCE BEHIND RELATIVISTIC SHOCK WAVES AND THEIR IMPLICATIONS FOR GAMMA-RAY BURSTS [J].

Inoue, Tsuyoshi ;

Asano, Katsuaki ;

Ioka, Kunihito .

ASTROPHYSICAL JOURNAL, 2011, 734 (02)

[9]

Kawabata K. S., 2008, P SOC PHOTO-OPT INS, V7014, P151

[10] Mass fall-back and accretion in the central engine of gamma-ray bursts [J].

Kumar, Pawan ;

Narayan, Ramesh ;

Johnson, Jarrett L. .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2008, 388 (04) :1729-1742

← 1 2 3 4 →