Kinematic structure of the inner zones of disc galaxies

Abstract

The kinematics of the inner zones of disc galaxies have recently been shown to be much more complicated than previously thought. New instruments and more sensitive detectors have allowed us to obtain spectra of higher S/N ratio and resolution, as well as images, for a more refined study of these inner zones. Decoupled kinematic cores have been known for some time to exist in ellipticals, but complex structures and their kinematic counterparts are now showing up in disc galaxies also. There is a variety of dynamical origins for these structures, and they can be detected sometimes in the gaseous component, sometimes in the stellar component, and sometimes in both. Here we give an overview of the components which are found with significant frequency, and explain how we can distinguish one from another. The components covered include black holes, inner cores, inner bars, inner discs, inner annuli, inner bulges, etc. In most cases a reliable diagnostic of the component structure would not be possible without combining high quality photometric observations with high quality kinematic observations.