Warm–hot intergalactic medium

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.

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]

See also

Look up warm-hot intergalactic medium in Wiktionary, the free dictionary.

References

  1. 1 2 Bykov, A. M.; Paerels, F. B. S.; Petrosian, V. (February 2008), "Equilibration Processes in the Warm-Hot Intergalactic Medium", Space Science Reviews, 134 (1–4): 141–153, arXiv:0801.1008Freely accessible, Bibcode:2008SSRv..134..141B, doi:10.1007/s11214-008-9309-4
  2. ↑ Reimers, D. (2002), "Baryons in the diffuse intergalactic medium", Space Science Reviews, 100 (1/4): 89, Bibcode:2002SSRv..100...89R, doi:10.1023/A:1015861926654
  3. ↑ http://www.space.com/scienceastronomy/chandra-missing-matter-100511.html
  4. ↑ http://www.skyandtelescope.com/astronomy-news/last-missing-normal-matter-is-found/



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