Maps of peak intensities (panel a), LSR velocities (panel b), linewidths (panel c), and Mach numbers (panel d) derived from single-component Gaussian fits to our C¹⁸ O (1–0) data. The color bars represent main beam brightness temperatures in units of K in panel a, LSR velocities in units of km s⁻¹ in panel b, and linewidths in units of km s⁻¹ in panel c. Velocity gradients along the filament and perpendicular to the filament are indicated by the blackand red arrows in panel b, respectively. In all panels, the (0, 0) offset corresponds to α_J2000 = 18^h28^m49.^s642, δ_J2000 = 00°50′01.′′08, and the three black crosses give the positions of the three embedded YSOs (see Fig. 1). The mean uncertainties in derived peak intensities, LSR velocities, linewidths, and Mach numbers are 0.19 K, 0.02 km s⁻¹, 0.06 km s⁻¹, and 0.1, respectively. The beam size is shown in the lower right of each panel.