Spatial distribution of the properties of residual [C II] line as described in Sect. 6.2: integrated line intensities (left), line center shift with respect to ¹²CO (1−0) (middle), and line width ratio between the residual [C II] and ¹²CO (1−0) (right). The positions with no residual [C II] are diagonally hatched. The baseline RMS of the residual [C II] line is between 42 and 98 mK. The error of the line intensity integrated over Δv is computed as with the number of frequency channels N. With channel widths of 2 K km s^-1, N = 15 for a line width of 30 km s^-1 and the total error is 0.3−0.8 K km s^-1. The spatial resolution is 14′′ and 18′′ for [C II] and [N II], respectively.