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Polarization Evolution of the Afterglow of GRB 030329The association of a supernova with GRB 030329l strongly supports the collapsar model of gamma-ray bursts (GRBs), where a relativistic jet forms after the progenitor star collapses. Such jets cannot be spatially resolved because of their cosmological distances. Their existence is conjectured based on breaks in GRB afterglow light curves and the theoretical desire to reduce the GRB energy requirements. Temporal evolution of polarization may provide independent evidence for the jet structure of the relativistic outflow. Small-level polarization (approx. 1-3%) has been reported for a few bursts, but the temporal evolution of polarization properties could not be established. Here, we report polarimetric observations of the afterglow of GRB 030329 with high signal-to-noise and high sampling frequency. We establish the polarization light curve, detect sustained polarization at the percent level, and find significant variability. The data imply that the afterglow magnetic field has small coherence length and is mostly random, probably generated by turbulence, in contrast with the high polarization detected in the prompt gamma-rays from GRB 02120618. Our results suggest a different structure and origin of the magnetic field in the prompt vs. afterglow emission regions.
Document ID
20030106172
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Greiner, Jochen
(Max-Planck-Inst. fuer Extraterrestrische Physik Garching, Germany)
Klose, Sylvio
(Thueringer Landessternwarte Tautenburg, Germany)
Reinsch, Klaus
(Universitaets-Sternwarte Goettingen, Germany)
Schmid, Hans Martin
(Eidgenoessische Technische Hochschule Zurich, Switzerland)
Sari, Re'em
(California Inst. of Tech. Pasadena, CA, United States)
Hartmann, Dieter H.
(Clemson Univ. SC, United States)
Kouveliotou, Chryssa
(National Space Science and Technology Center Huntsville, AL, United States)
Rau, Arne
(Max-Planck-Inst. fuer Extraterrestrische Physik Garching, Germany)
Palazzi, Eliana
(Consiglio Nazionale delle Ricerche Bologna, Italy)
Straubmeier, Christian
(Cologne Univ. Germany)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Astrophysics
Distribution Limits
Public
Copyright
Other

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