Early Optical Polarization of a Gamma-Ray Burst Afterglow

2007/03/16 by Carole G. Mundell, C. G. Mundell, I. A. Steele +21 · 81 citations
Chemistry · Physics and Astronomy · #Afterglow #Astro and Planetary Science #Astronomy #Astrophysics #Brightness #Chemistry #Ejecta #Gamma-ray burst #Gamma-ray bursts and supernovae #Optics #Physics #Polarimeter #Polarimetry #Polarization (electrochemistry) #Stellar, planetary, and galactic studies #Supernova #Telescope #astro-ph

paper · pdf · doi:10.1126/science.1138484

published in Science 315(5820), 1822-1824 (American Association for the Advancement of Science) · 8 pages including 1 figure. Accepted for publication in Science; published online 15 March 2007; 10.1126/science.1138484

openalex publication_date 2007/03/16 · arxiv created 2007/03/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We report the optical polarization of a gamma-ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma-rays from GRB 060418, using a ring polarimeter on the robotic Liverpool Telescope. Our robust (2sigma) upper limit on the percentage of polarization, less than 8%, coincides with the fireball deceleration time at the onset of the afterglow. The combination of the rate of decay of the optical brightness and the low polarization at this critical time constrains standard models of GRB ejecta, ruling out the presence of a large-scale ordered magnetic field in the emitting region.

Citations

• Polarization of the prompt γ-ray emission from the γ-ray burst of 6 December 2002
• Hydrodynamics of a Relativistic Fireball: The Complete Evolution
• Evidence of polarisation in the prompt gamma-ray emission from GRB 930131 and GRB 960924
• The Strongly Polarized Afterglow of GRB 020405
• The physics of gamma-ray bursts
• Optical Spectropolarimetry of the GRB 020813 Afterglow
• Magnetic Fields in Gamma-Ray Bursts: A Short Overview
• The polarization of afterglow emission reveals γ-ray bursts jet structure