•Hot
gas can also be studied by looking for decrements in the Cosmic
Background radiation, resulting from Compton scattering by
hot electrons. Net energy is
slightly increased.
Not a symmetric effect – in Rayleigh-Jeans
region there is decrement but in Wein region there is an
excess.
•
•First
predicted by Sunyaev and Zeldovich in 1969, and has been
observed.
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