Bottom: spatial distribution of the I([CII])_i/I([NII])_i integrated intensity ratio calculated for the radial velocity range −90 km s⁻¹ to +25 km s⁻¹. The AF traced by 20 cm continuum observations and the selected positions in Table 1 are shown as black contours and white circles, respectively. The white ⋆ symbol represents the location of the Arches Cluster. Top: histogram of the spatial distribution of I([CII])_i/I([NII])_i integrated intensity ratios shown in the map. A Gaussian fit was performed to the histogram to characterize the central ratio (R_c) and standard deviation (R_σ) of the distribution.