Shock Wave from a Galactic Nucleus into a Halo and Intergalactic Space

Abstract The propagation of a shock wave associated with an explosion at the nucleus of a disk galaxy through the halo and intergalactic gas is studied. An initially spherical shock front expands into the disk and halo, being elongated in the direction perpendicular to the disk plane. In the halo the front attains an Ω-shaped shell structure, which is observed as a large radio lobe in edge-on galaxies. We call attention to several galaxies in which such Ω-shaped radio lobes have been observed.