A structure factor approach to the Sunyaev–Zelʹdovich effect

Structure factor theory (SFT) is applied to analyze distortions to the cosmic microwave background radiation (CMBR) due the Sunyaev–Zelʹdovich Effect (SZE) in typical clusters of galaxies. It is shown that a suitable structure factor associated to a collisionless (Knudsen) gas is able to reproduce the SZE distortion of the CMBR . Physical arguments suggest that SFT yields an approximate solution to the Kompaneets equation and sets plausible values for the two “free” parameters involved in the calculation of the spectral distortion. Finally, further applications of the SFT to other standard cosmological problems are briefly discussed.