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The Strongly Polarized Afterglow of GRB 020405

D. Bersier·B. McLeod·P. M. Garnavich·M. J. Holman·T. Grav·J. Quinn·J. Kaluzny·P. M. Challis·R. G. Bower·D. J. Wilman·J. S. Heyl·S. T. Holland·V. Hradecky·S. Jha·K. Z. Stanek
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Abstract

We report polarization measurements and photometry for the optical afterglow of the gamma-ray burst GRB 020405. We measured a highly significant 9.9% polarization (in V band) 1.3 days after the burst and argue that it is intrinsic to the GRB. The light curve decay is well fitted by a $t^{-1.72}$ power-law; we do not see any evidence for a break between 1.24 and 4.3 days after the burst. We discuss these measurements in the light of several models of GRB afterglows.

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D. Bersier, B. McLeod, P. M. Garnavich, M. J. Holman, T. Grav, J. Quinn, J. Kaluzny, P. M. Challis, R. G. Bower, D. J. Wilman, J. S. Heyl, S. T. Holland, V. Hradecky, S. Jha, K. Z. Stanek. 2002-06-26. The Strongly Polarized Afterglow of GRB 020405. https://doi.org/10.1086/368158

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