Position-velocity diagram of the [CI](1−0) line emission (color scale) taken along the disk (upper panels a+b) and perpendicular to it (lower panels c+d; the slices are chosen such as that they go through the maximum peak of the line ratio map shown in Fig. 1c). The CO(J = 1−0) line emission (contours) is overlaid on that of [CI] in panels a) and c); the velocity resolution is 3 km s^-1. Panels b) and d) show the [CI](1−0)/CO line ratio map in brightness temperature scale overlaid with contours of the [CI] emission. The contours of the CO(J = 1−0) line emission are in steps of 30σ (1σ = 7.4 mJy/beam) in panel a) and c) and that of the [CI] emission goes in steps of 7σ (1σ = 150 mJy/beam) in panel b) and in steps of 5σ in panel d). The zero velocity corresponds to the kinematic LSR velocity of 236 km s^-1.