Sunyayev-Seldowitsch effect

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The Sunjajew-Seldowitsch effect (after Rashid Sunyaev and Jakow Borissowitsch Seldowitsch ; English transcription: Sunyaev-Zel'dovich effect, abbreviation of the SZ effect ) explains the lack and excess of low-energy or higher-energy photons in the cosmic microwave background that comes from direction of galaxy clusters is observed by the collision of photons with hot electrons .

The hot electrons contained in the medium of the clusters can scatter photons of the cosmic background radiation . The inverse Compton effect means that energy is transferred from the electrons to the photons, the frequency of which increases accordingly; the spectrum changes as described above compared to the original Planck spectrum .

With the help of the SZ effect, clusters of galaxies can be tracked down as "shadows" in front of the uniform spectrum of the cosmic background. The measurement of the Sunjajew-Seldowitsch effect and the search for distant galaxy clusters is one of the goals of the Planck mission .

literature

  • RA Sunyaev, Ya. B. Zel'dovich: Small-Scale Fluctuations of Relic Radiation . Astrophysics and Space Science 7, 1970, doi: 10.1007 / BF00653471 .
  • RA Sunyaev, Ya. B. Zel'dovich: Microwave background radiation as a probe of the contemporary structure and history of the universe . Annual Review of Astronomy and Astrophysics 18, 1980, doi: 10.1146 / annurev.aa.18.090180.002541 .
  • Peter Schneider: Introduction to Extragalactic Astronomy and Cosmology , Springer Verlag, Berlin 2005, ISBN 3-540-25832-9 , limited preview in the Google book search