Physical conditions in the intergalactic medium

Abstract

Measurements of the spectrum of the cosmic microwave background radiation by COBE (Cosmic Background Explorer) limit the line integral of the electron pressure in intergalactic gas out to cosmological distances. The internal physical properties of diffuse bridges in the lobes of giant radio galaxies are also expected to reflect directly the pressure in this intergalactic medium that forms the environment of the radio structure. Surprisingly, the COBE limits rule out an intergalactic medium with the pressure indicated by the radio structures. This suggests that these regions are not thermally confined