Spatial distribution of the synchrotron (left panel), mixed (central panel) and free–free (right panel) components of DS at 4 GHz. All the three images are obtained after fitting the observed SED with the sum of two power-law functions: S_th (ν) ∝ ν^−0.1 and S_nt (ν) ∝ ν^−0.7 for the thermal and non-thermal components, respectively (see details in Sect. 4.1.2). The contours are the same as in Fig. 5. All panels have a circular beam of 4′′ (shown in the bottom left corner of each panel). The dashed circles indicate the region in which we calculated the flux density of DS (see Sect. 4.1).