Velocity structure of the NGC 6334 extended region. Top: 2D histogram plot of ¹³CO velocity components in the full observed region projected along the longitudinal direction from east to west. The bin sizes are 300 × 300. The colour bar shows the counts. The dotted white line follows the median velocities at a given longitude. The longitude of the six FIR sources I[N], I, II, III, IV, and V, and also the GM24 region is indicated by the vertical dotted white markers. Also shown are the positions of the V-shaped velocity gradients (in cyan). Bottom: velocity and intensity variation along the longitude within the PV-sliced region in Fig. 5. The values on the y-axis are arbitrary numbers normalized by the mean values. The vertical black dotted lines indicate the longitudinal positions of the ATLASGAL clumps in the same region.