Comparison of (a) Herschel H₂ column density, (b) Nobeyama 45m C¹⁸O integrated intensity, and (c) Nobeyama 45m H¹³CO⁺ (1–0) integrated intensity maps with an angular resolution of 30″. Panel a is the same as Fig. 1, but the angular resolution is smoothed to be 30″. Panel b is the same as Fig. 2m, but the angular resolution is smoothed to be 30″. Panel c is the same as Fig. 4b. The black contours in each panel indicate the A_V column density levels of 8, 16, 24, 32, 64, 128, and 256 mag (assuming ; Bohlin et al. 1978).