²⁸SiO emissionintegrated over two velocity ranges (see text). EHV: –23 to –13 km s⁻¹, and HV: –13 to –3 km s⁻¹. The white contours start at 5σ, with steps of 15σ (rms = 14 and 45 mJy beam⁻¹ for the EHV and HV, respectively). The subclumps composing the B0 and B1 shock regions along the outflow of L1157 are marked here with circles (B0), triangles (B1), and squares (B2). The dashed circles represent the HPBW of the IRAM 30 m spectra at 86 GHz (29′′), 210 GHz (12′′), and 350 GHz(7.5′′). The green contours in the channel maps show the 10, 60, and 120σ levels of the integrated intensity map of ²⁸SiO, shown in Fig. 1.