Please use this identifier to cite or link to this item:
Title: Variable polarization in the optical afterglow of GRB021004
Authors: Rol, E.
Wijers, R. A. M. J.
Fynbo, J. P. U.
Hjorth, J.
Gorosabel, J.
Egholm, M. P.
Ceron, J. M. C.
Castro-Tirado, A. J.
Kaper, L.
Masetti, N.
Palazzi, E.
Pian, E.
Tanvir, N.
Vreeswijk, P.
Kouveliotou, C.
Moller, P.
Pedersen, H.
Fruchter, A. S.
Rhoads, J.
Burud, I.
Salamanca, I.
Van den Heuvel E. P. J.
First Published: 1-Jul-2003
Publisher: EDP Sciences for European Southern Observatory (ESO)
Citation: Astronomy & Astrophysics, 2003, 405 (3), pp. L23-L27
Abstract: 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 $t_{\rm b} \approx 1$ 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.
DOI Link: 10.1051/0004-6361:20030731
ISSN: 0004-6361
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2003 ESO. Reproduced with permission from Astronomy & Astrophysics, © ESO.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

Files in This Item:
File Description SizeFormat 
aafc184.pdfPublished (publisher PDF)102.18 kBAdobe PDFView/Open

Items in LRA are protected by copyright, with all rights reserved, unless otherwise indicated.