a) Distribution of the total brightness of the warm dust component with the contour map of the [OIII] line emission from the same data as in Fig. 4b. The contour levels are linearly drawn from 1 × 10^-6 to 3 × 10^-6 W m^-2 sr^-1. b) Distribution of the total brightness of the cold dust component with the contour map of the ¹²CO J = 1–0 emission integrated over the total velocity range (V_LSR =  −220 to  + 220 km s^-1; Oka et al. 1998). The contours are linearly drawn from 690 to 1200 K km s^-1. c) The contour maps of the ¹²CO J = 1–0 emission integrated over the velocity range of  − 30 to  − 10 km s^-1 and d) that over  + 20 to  + 40 km s^-1, both superimposed on the same distribution map of the warm dust component as shown in panel a). The contours are linearly drawn from 50 to 130 K km s^-1 for panel c) and from 160 to 240 K km s^-1 for panel d).