Vertical motions in the disk of NGC 5668 as seen with optical Fabry-Perot spectroscopy

摘要

We have observed the nearly face-on spiral galaxy NGC 5668 with the TAURUS IIFabry-Perot interferometer at the William Herschel Telescope using the$H\alpha$ line to study the kinematics of the ionized gas. From the extracteddata cube we construct intensity, velocity and velocity dispersion maps. Wecalculate the rotation curve in the innermost 2 arcmin and we use the residualvelocity field to look for regions with important vertical motions. Bycomparing the geometry of these regions in the residual velocity field with thegeometry in the intensity and velocity dispersion maps we are able to selectsome regions which are very likely to be shells or chimneys in the disk. Thegeometry and size of these regions are very similar to the shells or chimneysdetected in other galaxies by different means. Moreover, it is worth notingthan this galaxy has been reported to have a population of neutral hydrogenhigh velocity clouds (Schulman et al. 1996) which, according to theseobservations, could have been originated by chimneys similar to those reportedin this paper.