Abstract.
High resolution optical spectra acquired with the ESO New Technology Telescope
(NTT) + the ESO Multi Mode Instrument (EMMI) along the major axis of the
barred Sc starburst galaxy NGC 253 give detailed information on the kinematics
of the galaxy at different scales from the inner nuclear region up to
distances of 10 arcmin. We find strong evidence for a nuclear ring about 20
arcsec in diameter, with a circular velocity of 110 km/s, which is possibly
responsible for the gas supply to the nuclear starburst region of the galaxy.
The analysis of the dynamics of the bar in NGC 253 indicates that the nuclear
ring is related to the presence of an inner Lindblad resonance at about 300 pc
In this framework, the observed velocities indicate a mass in the central
10 arcsec of 3 x 10e8 solar masses . Good agreement is obtained
between the new optical data and published HI rotation curves at larger
radii.
Keywords. galaxies:individual (NGC 253) - galaxies: active - galaxies: ISM - galaxies: kinematics and dynamics