Evidence of Two Kinematically Different Stellar Systems in NGC 1068

Open Access
Publisher Website
Google Scholar
Abstract
We have obtained simultaneous two-dimensional spectroscopy of the Ca II triplet lines in the central 24'' × 20'' of NGC 1068, using an optical fiber system. The stellar velocity field derived from these data shows a kinematic off-centering between the inner (r < 3'') and outer (r > 5'') regions, indicative of a nonsymmetric gravitational potential. Both regions exhibit kinematic minor axes aligned with PA ~ 0° and could have similar systemic velocities. However, their kinematic centers are displaced by ~25. We propose that two kinematically different stellar systems rotating around parallel but shifted axes are present in NGC 1068. The origin of this peculiarity is discussed in relation to the gravitational potential of the galaxy and the hypothesis of a minor merger event.