Why study polarization of OAs?

Spectra and light curves of GRB afterglows match a synchrotron radiation model over a wide range of frequencies.
Synchrotron radiation is highly polarized (up to 70%), as verified in many astrophysical cases.
Optical polarization of GRB afterglows is small, (rarely greater than 2%), so theories of the origin of OAs must explain this.

Spectra and light curves of GRB afterglows match a synchrotron radiation model over a wide range of frequencies.