Intermittence of the map of the kinetic Sunyaev-Zel'dovich effect and turbulence of the intergalactic medium

Abstract

We investigate the possibility of detecting the turbulent state of the intergalactic medium (IGM) with the kinetic Sunyaev-Zel'dovich (kSZ) effect. Being sensitive to the divergence-free component of the momentum field of the IGM, the kSZ effect might be used to probe the vorticity of the turbulent IGM. With cosmological hydrodynamical simulation in the concordance ΛCDM universe, we find that the structure functions of two-dimensional kSZ maps show strong intermittence, and the intermittent exponents follow a law similar to the She-Leveque scaling formula of fully developed turbulence. We also find that the intermittence is weak in the maps of thermal Sunyaev-Zel'dovich (tSZ) effect. Nevertheless, the superposition of the kSZ and tSZ effects still contain significant intermittence. We conclude that the turbulent behavior of the IGM may be revealed by the observation of the SZ effect on angular scales equal to or less than 0.5 arcmin, corresponding to the multipole parameter l ≥ 2 × 104. © 2011. The American Astronomical Society. All rights reserved.