Megastructures of type-III civilizations orbiting galaxies

The article discusses the possibility of a Type-III extraterrestrial civilization constructing megastructures around a galaxy in regions where the galactic radiation becomes indistinguishable from the CMB radiation. For a Milky Way-like galaxy, we estimated the corresponding distance from its center at which a solar mass megastructure would need to be placed. We also showed that, from an energetic standpoint, placing such a massive object into orbit poses no fundamental difficulties. The detectability of the megastructure was also addressed.