Integrated intensity map (top panel) and velocity field map (bottom panel) of the N₂H⁺(1–0) emission towards the shock front in G034.77. In both panels, the pixels below 3×A_rms have been masked (Arms= 0.23 K km s⁻¹). The ${\mathrm{\Sigma }}_{{\text{H}}_2}=0.09\text{\hspace{0.17em}g\hspace{0.17em}}{\text{cm}}^{-2}$ (visual extinction 20 mag) magenta contour highlights the shape of the cloud (Kainulainen & Tan 2013). The SiO(2–1) emission contours obtained by Cosentino et al. (2019) is shown as black contours from 3σ (σ=0.016 Jy beam⁻¹ km s⁻¹) by steps of 3σ.