Variable polarization in the optical afterglow of GRB021004

被引：46

作者：

Rol, E

Wijers, RAMJ

Fynbo, JPU

Hjorth, J

Gorosabel, J

Egholm, MP

Cerón, JMC

Castro-Tirado, AJ

Kaper, L

Masetti, N

Palazzi, E

Pian, E

Tanvir, N

Vreeswijk, P

Kouveliotou, C

Moller, P

Pedersen, H

Fruchter, AS

Rhoads, J

Burud, I

Salamanca, I

Van den Heuvel, EPJ

机构：

[1] Univ Amsterdam, Astron Inst, NL-1098 SJ Amsterdam, Netherlands

[2] Univ Aarhus, Dept Phys & Astron, DK-8000 Aarhus, Denmark

[3] Univ Copenhagen, Astron Observ, DK-2100 Copenhagen, Denmark

[4] Inst Astrofis Andalucia, Granada 18008, Spain

[5] Space Telescope Sci Inst, Baltimore, MD 21218 USA

[6] Nord Opt Telescope, Tenerife 38700, Spain

[7] Real Inst & Observ Armada, Secc Astron, Cadiz 11110, Spain

[8] CNR, Ist Astrofis Spaziale & Fis Cosm, Sez Bologna, I-40129 Bologna, Italy

[9] Astron Observ Trieste, INAF, I-34131 Trieste, Italy

[10] Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England

[11] European So Observ, Santiago 19, Chile

[12] NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA

[13] European So Observ, D-85748 Garching, Germany

来源：

ASTRONOMY & ASTROPHYSICS | 2003年 / 405卷 / 03期

关键词：

gamma rays : bursts; polarization; radiation mechanisms : non-thermal;

D O I：

10.1051/0004-6361:20030731

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present polarimetric observations of the afterglow of gamma-ray burst (GRB) 021004, obtained with the Nordic Optical Telescope ( NOT) and the Very Large Telescope (VLT) between 8 and 17 hours after the burst. Comparison among the observations shows a 45 degree change in the position angle from 9 hours after the burst to 16 hours after the burst, and comparison with published data from later epochs even shows a 90 degree change between 9 and 89 hours after the burst. The degree of linear polarization shows a marginal change, but is also consistent with being constant in time. In the context of currently available models for changes in the polarization of GRBs, a homogeneous jet with an early break time of t(b) approximate to 1 day provides a good explanation of our data. The break time is a factor 2 to 6 earlier than has been found from the analysis of the optical light curve. The change in the position angle of the polarization rules out a structured jet model for the GRB.

引用

页码：L23 / L27

页数：5

共 45 条

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