Stellar and gas kinematics of NGC 4546, the double-spin SBO

Photometric, spectroscopic, optical and neutral hydrogen observations are presented of NGC 4546, a barred S0 galaxy possessing a disc of gas rotating in the opposite direction compared to the stellar disc. The relative circular velocities exceed 350 km s-1. The stellar velocity dispersion and the width of the emission lines within the galaxy are analysed. Hα imaging reveals a bright condensation close to the centre of the galaxy, possibly a remnant of the centre of a small galaxy captured by NGC 4546. Dust lanes, pseudo spiral arms and faint objects similar to globular clusters are also revealed after a model for the light distribution of the disc and the bulge has been subtracted from the image. (author)