Central kiloparsec of Seyfert and inactive host galaxies: a comparison of two-dimensional stellar and gaseous kinematics

We investigate the properties of the two-dimensional distribution and kinematics of ionized gas and stars in the central kiloparsec of a matched sample of nearby active (Seyfert) and inactive galaxies, using the SAURON integral field unit on the William Herschel Telescope. The ionized gas distributions show a range of low-excitation regions, such as star formation rings in Seyfert and inactive galaxies, and high-excitation regions related to photoionization by the active galactic nucleus (AGN). The stellar kinematics of all galaxies in the sample show regular rotation patterns typical of disc-like systems, with kinematic axes that are well aligned with those derived from the outer photometry and provide a reliable representation of the galactic line of nodes. After removal of the non-gravitational components due to, for example, AGN-driven outflows, the ionized gas kinematics in both the Seyfert and inactive galaxies are also dominated by rotation with global alignment between stars and gas in most galaxies. This result is consistent with previous findings from photometric studies that the large-scale light distribution of Seyfert hosts is similar to that of inactive hosts. However, by fully exploiting the two-dimensional nature of our spectroscopic data, deviations from axisymmetric rotation in the gaseous velocity fields are identified, which suggest that the gaseous kinematics are more disturbed at small radii in the Seyfert galaxies compared with the inactive galaxies. This provides a tentative link between nuclear gaseous streaming and nuclear activity.