Computed structure first masked from the density map. The external tides from all outside material sustained by a point in the computed structure was calculated pixel by pixel and is illustrated by orange lines. (a) Background representing the column density map derived from ATLASGAL+Planck 870 µm data. The material in the FOV of the ALMA observation (white region) was masked. (b) Background representing the column density map derived from H¹³CO⁺ J = 1−0 and HCO⁺ J = 1−0 lines from the ALMA observation by the LTE analysis.