Cutouts of several sky maps toward the HII region Sh 2-27. The images show a) ${\text{L}}_{{\text{DM}}^2/\text{EM}}$, b) ${\overline{B_{\Vert }}}_{gal}$, c) ϱ_EM/DM, and d) the foreground reduced B_‖gal image from Raycheva et al. (2022), which is derived from diffuse polarized radio emission. The contours of the latter image are plotted over the first three images, with contour lines set at −2 µG (light blue) and −6 µG (dark blue). The elliptic boundary in d) indicates the projected boundaries of Sh2-27 assumed in Raycheva et al. (2022).