Redshift space distortions in illustris free#

If unmodeled these effects prevent one from extracting cosmological information from RSD surveys. Numerical simulations show that redshift space distortions (RSD) introduce strong scale dependence in the power spectra of halos, with ten percent deviations relative to linear theory predictions even on relatively large scales (k < 0.1h/Mpc) and even in the absence of satellites (which induce Fingers-of-God, FoG, effects). As a result, our results can precisely predict the non-linear behavior of the density-weighted velocity field in redshift space up to ∼ 30 h, which means that these effects need to be understood if we want to extract cosmological information from the redshift space distortions.

Redshift space distortions in illustris free#

Our model can explain this characteristic feature without any free parameters. One of the most important features of density-weighted velocity statistics in redshift space is the change in sign of the cross-correlation between the density and density-weighted velocity at mildly small scales due to nonlinear redshift space distortions.

Using this relation, we can then extend familiar perturbation expansion techniques to the kSZ power spectrum. We show a simple relation between the density power spectrum and the density-weighted velocity power spectrum that holds for both dark matter and halos. This paper presents an analytical method to predict the power spectrum and two-point correlation function of the density-weighted velocity in redshift space, the direct observables in kSZ surveys. Observations of the kinetic Sunyaev-Zel'dovich (kSZ) effect measure the density-weighted velocity field, a potentially powerful cosmological probe.