BAR-DRIVEN EVOLUTION OF SOS - THE EDGE-ON GALAXY NGC-4570

We present circumstantial evidence that the central region of the edge -on SO galaxy NGC 4570, which harbours a 150-pc scale nuclear disc in addition to its main outer disc, has been shaped under the influence o f a small (similar to 500 pc) bar. This is based on the discovery of t wo edge-on rings, the locations of which are consistent with the inner Lindblad and ultraharmonic resonances of a rapidly tumbling triaxial potential. Observed features in the photometry and rotation curve corr espond nicely with the positions of the main resonances, strengthening the case for a tumbling bar potential. The relative blue colour of th e ILR ring, and the complete absence of any detected ISM, indicates th at the nuclear ring is made of relatively young (less than or similar to 2 Gyr) stars. We discuss a possible secular evolution scenario for this complex multicomponent galaxy, which may also apply to many other SO galaxies with observed rings and/or multiple disc components.