NGC 7479 A case study

The most salient features of the barred spiral galaxy NGC 7479 include the unusually strong and long bar, asymmetric spiral structure and peculiar dus t lanes. The central, bar-dominated region has been robbed of neutral atomi c gas. The neutral hydrogen kinematics of the strong western spiral arm are consistent with substantial non-circular motions. In contrast, the molecul ar gas is strongly concentrated in the nucleus and along the bar dust lanes . A molecular disc with near-circular motion is found in the nuclear area. Outside this component, the molecular gas has a strong radial velocity comp onent consistent with inflow. The velocity gradients across the bar dust la nes show jumps of a few hundred km s(-1). A comparison of the dust/gas lane morphology between the observations and numerical simulations suggests tha t the corotation radius is at 1.1 times the bar length. I have modelled man y of the peculiar morphological and kinematic features in numerical simulat ions of a minor merger. The predicted position of the merging companion mat ches the position of a bright clump in the bar with perturbed kinematics.