Polarized image of an equatorial emitting ring around a 4D Gauss–Bonnet black hole

We have studied the polarized image of an equatorial emitting ring around a 4D Gauss-Bonnet black hole. Our results show that effects parameter on depend magnetic field configuration, observation inclination angle, and fluid velocity. As lies in plane, observed polarization intensity increases monotonously with low angle case, its monotonicity disappears case high angle. However, as is vertical to increasing function case. The changes electric vector position both cases are more complicated. also probe Strokes $Q$-$U$ loops.