Results of C¹⁸O (1–0) and dust emission analysis along the cloud filament length. (a) Hydrogen column density derived using Herschel PACS and SPIRE images. (b) Dust temperatures. (c) Centroid velocity of C¹⁸ O obtained from Gaussian fitting of profiles (filled dots). The centroid velocities obtained using hyperfine fitting of the N₂H⁺ (1–0) line coinciding with the positions along the filament are marked by filled stars. (d) Mach number, which is the ratio of the nonthermal velocity dispersion (σ_nt) along the line of sight and the isothermal sound speed (c_s) at 10 K (~0.19 km s⁻¹). The blue line at 0.2 pc and the black line at 0.65 pc show the position of clump C2 and theclass 0 protostar L1157-mm, respectively. (e) Main-beam brightness temperature using C¹⁸ O lines.