Implications of the Large Polarization Measured in Gamma Ray Bursts

TL;DR

This paper reports high polarization measurements in gamma-ray bursts, supporting the Cannonball model over standard synchrotron models and offering a new test for understanding GRB and XRF phenomena.

Contribution

It provides the first polarization measurements in bright GRBs that align with the Cannonball model's predictions, challenging standard models.

Findings

Polarization nearly maximal in all observed GRBs

Results support the Cannonball model over synchrotron models

Predictions for XRFs and luminous GRBs differ in polarization levels

Abstract

The polarization of the prompt $\gamma$-ray emission has been measured in four bright gamma ray bursts (GRBs). It was nearly maximal in all cases, as predicted by the Cannonball (CB) model of GRBs long before the observations. These results are inconsistent with standard models of GRBs wherein the prompt emission is due to synchrotron radiation. A much smaller linear polarization is predicted by the CB model for the prompt emission in X-ray flashes (XRFs) and in extremely luminous GRBs. These measurements would provide yet another stringent test of the CB model and its unification of GRBs and XRFs.