Left: panel (a) depicts the 3D volume rendering of the velocity component lateral to the jet axis (see Sec. 4 for details) for dense gas (n ≥ 10 cm⁻³), from the simulations of jet–ISM interaction in Fabbiano et al. (2022). A 2D cross-section of this image in the X − Z plane is shown in panel (c). The red and blue colours show oppositely directed flows with respect to the jet-axis, expanding as a bubble. The pair of relativistic jets are presented using the contours of |v| = 0.1 c in green and magenta. Panel (b) shows the cross-section of the gas density in X − Z plane. Right: cartoon image representing the proposed model of the evolution of a jet-driven bubble in the southern jet, where the line of sight traces both sides of the expanding bubble.