Velocity structure of the central region. The left three panels show integrated H₂CO(3_2,2–2_2,1) maps for different velocity regimes as marked. The right panel presents a corresponding position–velocity cut from east to west along the line shown in the right panel of Fig. 3 and in the 2nd panel from left here. The dashed vertical lines in all panels mark the RA positions of the two central cores mm1 and mm2 (right and left dashed lines, respectively), where mm1 also drives a molecular outflow in northwest–southeast direction (Beuther et al. 2019). The horizontal dashed line in the pv-diagram shows the v_LSR ∼ −3.6 km s⁻¹ from Leurini et al. (2011a). Other features are marked and labeled.