The warm–hot intergalactic medium (WHIM) refers to a sparse, warm-to-hot (105 to 107 K) plasma that cosmologists believe to exist in the spaces between galaxies and to contain 40–50%[1] of the baryons (that is, 'normal matter' which exists as plasma or as atoms and molecules, in contrast to dark matter) in the universe at the current epoch.[2]Because of the high temperature of the medium, the expectation is that it is most easily observed from the ultraviolet and low energy X-ray emission. It can also be described as web of hot, diffuse gas.[1] To locate the WHIM, researchers examined X-ray observations of a rapidly growing super massive black hole known as an active galactic nucleus, or AGN.[2]

WHIM

Within the WHIM, gas shocks are created as a result of active galactic nuclei, along with the gravitationally-driven processes of merging and accretion. Part of the gravitational energy supplied by these effects is converted into thermal emissions of the matter by collisionless shock heating.[1]

In May 2010 a giant reservoir of WHIM was detected by the Chandra X-ray Observatory lying along the wall shaped structure of galaxies (Sculptor Wall) some 400 million light-years from Earth.[3][4]

  1. ^ "Huge Chunk of Universe's Missing Matter Found". Space.com. Retrieved 2016-12-05.
  2. ^ "Huge Chunk of Universe's Missing Matter Found". Space.com. Retrieved 2016-12-05.