RRM and GRM maps made by interpolation to the nearest pixel of the estimated value at the particular position of a source from our catalog with the annulus method. The black contour corresponds to y_bdry = 4.24 × 10⁻⁶ (same as in Fig. 1; see Sect. 3.3). The centers of the clusters and groups are represented by black crosses, while the dash-dotted circles represent their r₅₀₀. Left: Residual rotation measure map. The random nature of the patches in the map with similar sizes between them indicates that we have removed the larger coherent RM structure of the foreground Galactic contribution, while retaining the information about the SSC. Right: GRM map. Contrary to the behavior of the patches in the RRM map, this map exhibits a large continuous gradient in the RMs, which is expected for the large-scale Galactic contribution.