Query : 2019A&A...627A.105B

2019A&A...627A.105B - Astronomy and Astrophysics, volume 627A, 105-105 (2019/7-1)

Time-resolved GRB polarization with POLAR and GBM. Simultaneous spectral and polarization analysis with synchrotron emission.


Abstract (from CDS):

Context. Simultaneous γ-ray measurements of γ-ray burst spectra and polarization offer a unique way to determine the underlying emission mechanism(s) in these objects, as well as probing the particle acceleration mechanism(s) that lead to the observed γ-ray emission. Aims. We examine the jointly observed data from POLAR and Fermi-GBM of GRB 170114A to determine its spectral and polarization properties, and seek to understand the emission processes that generate these observations. We aim to develop an extensible and statistically sound framework for these types of measurements applicable to other instruments. Methods. We leveraged the existing 3ML analysis framework to develop a new analysis pipeline for simultaneously modeling the spectral and polarization data. We derived the proper Poisson likelihood for γ-ray polarization measurements in the presence of background. The developed framework is publicly available for similar measurements with other γ-ray polarimeters. The data are analyzed within a Bayesian probabilistic context and the spectral data from both instruments are simultaneously modeled with a physical, numerical synchrotron code. Results. The spectral modeling of the data is consistent with a synchrotron photon model as has been found in a majority of similarly analyzed single-pulse gamma-ray bursts. The polarization results reveal a slight trend of growing polarization in time reaching values of ∼30% at the temporal peak of the emission. We also observed that the polarization angle evolves with time throughout the emission. These results suggest a synchrotron origin of the emission but further observations of many GRBs are required to verify these evolutionary trends. Furthermore, we encourage the development of time-resolved polarization models for the prompt emission of gamma-ray bursts as the current models are not predictive enough to enable a full modeling of our current data.

Abstract Copyright: © J. M. Burgess et al. 2019

Journal keyword(s): polarization - gamma-ray burst: general - methods: data analysis - methods: statistical

Simbad objects: 2

goto Full paper

goto View the references in ADS

Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 GRB 041219 gB 00 24 27.7 +62 50 34           ~ 223 1
2 Fermi bn170114917 gB 00 48 -12.6           ~ 22 0

To bookmark this query, right click on this link: simbad:objects in 2019A&A...627A.105B and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact