The Westerbork Hydrogen Accretion in Local Galaxies (HALOGAS) survey : NGC 3198 and its extraplanar H I gas

I am showing a selection of results of the Westerbork Hydrogen Accretion in Local Galaxies survey, concentrating on the galaxy NGC 3198. The goal of the survey is to investigate the presence, morphology and kinematics of extraplanar neutral hydrogen gas. The presence of extraplanar gas in the spiral galaxy NGC 3198 is revealed for the first time, by making models of the observations. The extraplanar gas has a lower rotation velocity with increasing height from the midplane, with a vertical gradient of similar to 10 km s(-1) kpc(-1). Global (but preliminary) results of the survey sample are also briefly mentioned