Re-analysis of polarization in the γ-ray flux of GRB 021206

By R. Rutledge, D. Fox. 2003

135 citations recorded by the source corpus.

A previous analysis of the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observation of GRB 021206 found that the γ-ray flux was 80 ± 20 per cent polarized. We re-examine these data and find no signal that can be interpreted as due to polarization. First, we find that the number of scattering events suitable for measuring polarization – having been scattered from one detector to another, with a count produced in both – is considerably lower than estimated by Coburn & Boggs, by a factor of 10 (830 ± 150, versus 9840 ± 96). The signal-to-noise ratio of the data set is thus too low to produce a detection, even from a 100 per cent polarized source. None the less, we develop a polarization-detection analysis limited in sensitivity only by Poisson noise, which does not require a spacecraft mass model to detect polarization, as in Coburn & Boggs. We find no signal which might be interpreted as due to polarization of GRB 021206. Separately, we reproduce the Coburn & Boggs signal and show that it is not due to polarization. Rather, the Coburn & Boggs signal is consistent with the previously neglected systematic uncertainty in the ‘null light curve’ used for detection. Due to the low signal-to-noise ratio of the RHESSI data, our Poisson noise-limited analysis results in an upper limit consistent with 100 per cent polarization of the γ-ray flux from GRB 021206. Thus, no observational constraint on the polarization of GRB 021206 can be derived from these data.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/cc5e723eb41e77b7e5f7f9f3a09a94873a428a68

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In Astronomy and Astrophysics

Citations in the corpus

DETECTION OF GAMMA-RAY POLARIZATION IN PROMPT EMISSION OF GRB 100826A (2011, background): “…report was the detection of a high linear polarization of Π = 80 ± 20 % at a confidence level of > 5.7 σ by RHESSI from GRB 021206 (Coburn & Boggs 2003), although independent groups could not confirm any polarization signals by reanalyzing the same data (Rutledge & Fox 2004; Wigger et al. 2004).”
Modern Tests of Lorentz Invariance (2005, methodology): “Recently, the reported polarization of GRB021206 [85] was used to constrain ξ to |ξ| < O(10−14) [156], but since the polarization claim is uncertain [248, 274] such a figure cannot be treated as an actual constraint.”
THE INTERNAL-COLLISION-INDUCED MAGNETIC RECONNECTION AND TURBULENCE (ICMART) MODEL OF GAMMA-RAY BURSTS (2010, background): “However, a further analysis of the same data cannot confirm the claim (Rutledge and Fox 2004).”