The ionized gas in the spiral galaxy NGC 3359 II. Kinematics

The spiral galaxy NGC 3359 has been observed in the H alpha line with the T AURUS II Fabry-Perot interferometer at the William Herschel Telescope withi n the BARS programme on the Canary Island telescopes in order to study the kinematics of the ionized gas. We have produced maps of velocity and velocity dispersion, and computed the rotation curve out to similar to 3 scale lengths from the centre of the ga laxy. From the map of the residual velocities, obtained after subtracting o ff the systemic rotation, we detected streaming motions in the gas across t he spiral arms and the presence of non-circular motions of order 30 - 40 km s(-1) around the bar: the gas response to the gravitational potential. The velocity dispersion map shows typical values of order 15 km s(-1) for the HII regions, but also reveals major wings of high dispersion associated wit h the most luminous, density-limited regions.