Cartoon of the star formation scenario around HW2, where the observer is placed to the right for clarity. The line-of-sight to HW2, slightly above the disk mid-plane by 26° (Sanna et al. 2017), crosses a column of NH₃ gas infalling in front of a region of bright continuum emission, confined inside the inner 200 au. At larger radii, the observer maps emission from NH₃ gas (molecular structure sketched to the left), which is both infalling (v_r) by gravity toward the central star and rotating (v_ϕ) at sub-Keplerian velocities. Atomic (ionised) gas is also ejected away along the general direction of the system angular momentum, with a lobe of blue-shifted (approaching to the observer) gas to the north and one of red-shifted (receding) gas to the south (e.g., Gómez et al. 1999).