The contribution of the kinematic Sunyaev-Zel'dovich Effect from the Warm Hot Intergalactic Medium to the Five-Year WMAP Data

TL;DR

This study investigates the impact of the kinematic Sunyaev-Zel'dovich effect from the warm-hot intergalactic medium on WMAP data, finding a modest but notable contribution that could be better confirmed with future observations.

Contribution

It introduces a new model component for the kSZ effect from the WHIM and assesses its impact on cosmological parameter estimation using WMAP data.

Findings

kSZ effect from WHIM improves fit at high multipoles

contribution peaks at l~450 with 3.1% of total power

null kSZ contribution still compatible within 2-sigma

Abstract

We study the contribution of the kinematic Sunyaev-Zel'dovich (kSZ) effect, generated by the warm-hot intergalactic medium (WHIM), to the cosmic microwave background (CMB) temperature anisotropies in the Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) data. We explore the concordance LambdaCDM cosmological model, with and without this kSZ contribution, using a Markov chain Monte Carlo algorithm. Our model requires a single extra parameter to describe this new component. Our results show that the inclusion of the kSZ signal improves the fit to the data without significantly altering the best-fit cosmological parameters except Obh^2. The improvement is localized at the l>500 multipoles. For the best-fit model, this extra component peaks at l~450 with an amplitude of 129 muK^2, and represents 3.1% of the total power measured by the Wilkinson Microwave Anisotropy Probe. Nevertheless, at the 2-sigma level a null kSZ contribution is still compatible with the data. Part of the detected signal could arise from unmasked point sources and/or Poissonianly distributed foreground residuals. A statistically more significant detection requires the wider frequency coverage and angular resolution of the forthcoming Planck mission.