The velocity field of the barred spiral galaxy NGC 5383

The considered galaxy NGC 5383 is one of the few bright barred spiral galaxies in the northern sky. Pease (1917) has noted the existence of a faint, very low-surface-brightness companion spiral 3'.1 to the south. It is shown that the companion galaxy has a velocity close to that of NGC 5383. The two form, therefore, probably an interacting pair. A description is given of optical spectra at high spatial and high-velocity resolution which have been obtained with the aid of a two-stage Carnegie image-tube spectrograph. Radio observations of NGC 5383 at 21 cm with a 91.4-m transit radio telescope are also considered. It is found that the emission-line velocity field of NGC 5383 does not resemble that expected for a pattern of circular motions only. The velocities in the bar and the spiral arm region can be most closely reproduced by a simple rotation in a disk which is substantially warped.