SiO(5–4) emission in the blue lobe of the L1157 outflow integrated in two velocity ranges. The high-velocity range (left panel) is integrated from –16.7 to –6.3 km s^-1, the low-velocity range (right panel) from –6.3 to +4.1 km s^-1. The velocity range is indicated in the upper left corner of each panel. Contours start at 3σ and are then separated by steps of 1σ (σ = 0.985 Jy beam^-1 km s^-1). The grayscale represents the 4.5 μm emission from Spitzer/IRAC.