Supershells, Fountains and Chimneys in Galaxies

A brief overview of large-scale flamentary-cellular structures arising in the process of active life of any gas-rich galaxy is presented, such as expanding superbubbles and supershells, channels providing gas outflows (chimneys), powerful flows of matter ejected over large distances from the galaxy into the circumgalactic environment (fountains). The review includes general conceptual ideas about the origin of the structures under consideration, observational data, as well as methods and techniques for analyzing the formation and evolution of structures. Based on the results of computer modeling, a conclusion was made about the presence of an intermediate asymptotic stage of the expansion of supershells, which had not previously been noted in the concepts of the evolution of the interstellar medium in disk galaxies. The disk matter is swept out by collective supernova explosions to great galactic heights into the gas halo, and if there is a significant amount of cloud component in the interstellar medium, the flow takes the form of a mudflow, forming multiple channels (chimneys), surrounded by dense walls of cloud phase matter. The widespread view in interstellar physics that galactic chimneys function like chimneys in terrestrial structures and technical systems, creating chimney draft, is not correct.