Detection significance of X-ray polarization for 1ES 1101-232 (left) and RGB J0710+591 (right), as measured from the spectropolarimetric analysis. The tangential direction indicates the polarization angle, and the radial direction corresponds to the polarization degree. The colored dot at the center of each contour denotes the measured X-ray polarization. Contours correspond to detection confidence levels of 68%, 90%, and 99%.