Polar structures in late-type galaxies

Abstract

A common point of view is that stable polar structures are mainly present in the E/S0 early-type galaxies lacking dense gas in their host disks. However, nuclear, as well as external polar rings and disks also exist in the late-type hosts, including gas-rich dwarf galaxies. Using the 3D spectroscopic observations of these objects we can derive the rotation properties of the gas components separately in the main and polar planes. The most detailed picture of the gas kinematics and mass distribution properties could be obtained from the combination of optical (H II) and radio (H I) data sets. I briefly review the results of such studies, including the observations of the direct interaction between the multi-spin gas components.