Ten per cent polarized optical emission from GRB 090102

I. A. Steele, C. G. Mundell, R. J. Smith, S. Kobayashi, C. Guidorzi

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104 Citations (Scopus)


The nature of the jets and the role of magnetic fields in gamma-ray bursts (GRBs) remains unclear. In a baryon-dominated jet only weak, tangled fields generated in situ through shocks would be present. In an alternative model, jets are threaded with large-scale magnetic fields that originate at the central engine and that accelerate and collimate the material. To distinguish between the models the degree of polarization in early-time emission must be measured; however, previous claims of gamma-ray polarization have been controversial. Here we report that the early optical emission from GRB 090102 was polarized at 10 1 per cent, indicating the presence of large-scale fields originating in the expanding fireball. If the degree of polarization and its position angle were variable on timescales shorter than our 60-second exposure, then the peak polarization may have been larger than ten per cent.

Original languageEnglish
Pages (from-to)767-769
Number of pages3
Issue number7274
Publication statusPublished - 10 Dec 2009

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    Steele, I. A., Mundell, C. G., Smith, R. J., Kobayashi, S., & Guidorzi, C. (2009). Ten per cent polarized optical emission from GRB 090102. Nature, 462(7274), 767-769. https://doi.org/10.1038/nature08590