Left: maps of the ¹³CO/C¹⁸O abundance ratio obtained from the ¹³CO and C¹⁸O J = 2–1 lines assuming LTE. Contours are the H₂ column density in levels of (0.9, 1.1, 1.3, 1.5, 1.9, 2.4, 3.0, 4.0, and 5.0) × 10²² cm⁻². Magenta ellipses mark the dust clumps. Part of the black dashed circle indicates the infrared bubble MWP1G326725+007745. The main and branched skeletons are shown as white and black curves, respectively. The beam size of the CO observation is shown in the lower right corner. Magenta ellipses mark the dust clumps. Right: projected local gravitational field (gray arrows) overlaid on the H₂ column density contours in levels of (0.9, 1.1, 1.3, 1.5, 1.9, 2.4, 3.0, 4.0, and 5.0) × 10²² cm⁻² and the color-coded velocity centroids of C¹⁸O (J = 2–1). The sizes of the symbols indicate the line width of C¹⁸O (J = 2–1). The gravitational force vectors are displayed with uniform lengths to emphasize their directions.