SunyaevZeldovicheffekten

The Sunyaev-Zel'dovich effect is a phenomenon observed in the cosmic microwave background (CMB) radiation. It occurs when CMB photons scatter off hot, ionized gas in galaxy clusters. This scattering causes a distortion in the CMB spectrum, leading to a slight deficit of photons at certain frequencies and an excess at others. The effect is named after Rashid Sunyaev and Yakov Zel'dovich, who predicted it in 1970.

There are two primary forms of the Sunyaev-Zel'dovich effect: the thermal Sunyaev-Zel'dovich (tSZ) effect and the kinetic Sunyaev-Zel'dovich (kSZ) effect. The tSZ effect arises from the thermal motion of electrons in the hot gas, while the kSZ effect is due to the bulk motion of the galaxy cluster itself relative to the CMB rest frame.

The Sunyaev-Zel'dovich effect is a powerful tool for studying galaxy clusters and cosmology. By measuring the amplitude and frequency dependence of the effect, astronomers can determine the temperature and density of the hot gas within clusters, as well as the cluster's mass and distance. This information is crucial for understanding the formation and evolution of large-scale structures in the universe and for constraining cosmological parameters, such as the Hubble constant and the density of dark matter. Observations of the Sunyaev-Zel'dovich effect have provided independent measurements of these parameters, which are consistent with results from other cosmological probes.