Polarimetric Analysis of the Long Duration Gamma Ray Burst GRB 160530A With the Balloon Borne Compton Spectrometer and Imager

Abstract

A long duration gamma-ray burst, GRB 160530A, was detected by the Compton Spectrometer and Imager (COSI) during the 2016 COSI Super Pressure Balloon campaign. As a Compton telescope, COSI is inherently sensitive to the polarization of gamma-ray sources in the energy range 0.2-5.0 MeV. We measured the polarization of GRB 160530A using 1) a standard method (SM) based on fitting the distribution of azimuthal scattering angles with a modulation curve, and 2) an unbinned, maximum likelihood method (MLM). In both cases, the measured polarization level was below the $99\%$ confidence minimum detectable polarization levels of $72.3\pm 0.8\%$ (SM) and $57.5\pm 0.8\%$ (MLM). Therefore, COSI did not detect polarized gamma-ray emission from this burst. Our most constraining $90\%$ confidence upper limit on the polarization level was $46\%$ (MLM).

For more information regarding our implementation of maximum likelihood Compton polarimetry, please see our accompanying paper "Maximum Likelihood Compton Polarimetry with the Compton Spectrometer and Imager"

References in corpus (4)

• The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts
• POLAR, a compact detector for Gamma Ray Bursts photon polarization measurements
• High Energy Polarimetry of Prompt GRB Emission
• Maximum Likelihood Compton Polarimetry with the Compton Spectrometer and Imager

Cited by in corpus (13)

• Detailed polarization measurements of the prompt emission of five Gamma-Ray Bursts
• Calibrations of the Compton Spectrometer and Imager
• EUSO-SPB1 Mission and Science
• Benchmarking simulations of the Compton Spectrometer and Imager with calibrations
• Probing the Galactic Diffuse Continuum Emission with COSI
• Maximum Likelihood Compton Polarimetry with the Compton Spectrometer and Imager
• Soft gamma-ray polarimetry with COSI using maximum likelihood analysis
• Gamma-Ray Polarimetry
• Compton Telescopes for Gamma-ray Astrophysics
• Telescope Concepts in Gamma-Ray Astronomy
• Proton Irradiation of SiPM arrays for POLAR-2
• Enhancing Compton telescope imaging with maximum a posteriori estimation: a modified Richardson-Lucy algorithm for the Compton Spectrometer and Imager
• Imaging and Spectral Fitting of Bright Gamma-ray Sources with the COSI Balloon Payload