Intensities of molecular lines in the PVDs along the major axis. The major axis of NGC 253 is marked by the solid black line in Fig. 1a, on which the black arrow shows the positive direction of position. (a) CO(1–0) PVD. The gray contours are drawn at [2, 10] K, and the blue contours are drawn at [20, 30] K. The white arrow points to the SW streamer and remains the same in the following panels. (b) ¹³CO(1–0) PVD. The gray contours are drawn at [0.3, 1.2, 2.0, 3.5] K. (c) HCN(1–0) PVD. The gray contours are drawn at [0.3, 1.2, 2.0, 3.5] K. (d) H¹³CN(1–0) PVD. The gray contours are drawn at [0.06, 0.25, 0.45] K and the blue contour is drawn at 0.62 K. (e) SiO(2–1) PVD. The gray contours are drawn at [0.06, 0.25, 0.45] K and the blue contour is drawn at 0.62 K. (f) CH₃OH(2_k–1_k) PVD. The gray contours are drawn at [0.12, 0.50, 1.00, 1.50] K.