Cooling flows within galactic haloes: the kinematics and properties of   infalling multi-phase gas
  We study the formation of disks via the cooling flow of gas within galactic haloes using smoothed particle hydrodynamics simulations. These simulations resolve mass scales of a few thousand solar masses in the gas component for the first time. Thermal instabilities result in the formation of numerous warm clouds that are pressure confined by the hot ambient halo gas. The clouds fall slowly onto the disk through non-spherical accretion from material flowing preferentially down the angular momentum axis. The rotational velocity of the infalling cold gas decreases as a function of height above the disk, closely resembling that of the extra-planar gas recently observed around the spiral galaxy NGC 891. 
Tobias Kaufmann (1), Lucio Mayer (1), James Wadsley (2), Joachim   Stadel (1), Ben Moore (1), ((1) University of Zurich, (2)...