Galactic fountains [chapter]

F. D. Kahn
Structure and Dynamics of the Interstellar medium  
The intercloud medium (ICM) is kept hot and supplied with gas by supernova remnants of Type II. The rate at which mass is added balances the rate at which gas flows away from the ICM into the galactic halo. A fountain is thus formed, since the gas only has enough energy to escape from the disk, but not from the Galaxy as a whole. The upward flow must be followed by the descent of the gas, in the form of a shocked sheet: the return flow seems to be observed in the form of intermediate velocity
more » ... rmediate velocity clouds. These conclusions will be modified if cosmic ray pressure is important, or if there is a significant inflow of extragalactic gas into the halo.
doi:10.1007/bfb0114921 fatcat:lag5po4zovc2hih4me67fvmzty