The extra-planar neutral gas in the edge-on spiral galaxy NGC 891
  We present neutral hydrogen observations of the nearby edge-on spiral galaxy NGC891 which show extended extra-planar emission up to distances of 15 kpc from the plane. 3D modeling of the galaxy shows that this emission comes from halo gas rotating more slowly than the gas in the disk.We derive the rotation curves of the gas above the plane and find a gradient in rotation velocity of -15 km/s/kpc. We also present preliminary results of a galactic fountain model applied to NGC891. 
Filippo Fraternali (University of Oxford), Tom Oosterloo (ASTRON),   Renzo Sancisi (INAF-Bologna & Kapteyn), Rob Swaters (Un...