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arXiv 0905.2582astro-ph.CO
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来自温热星系际介质的运动学Sunyaev-Zel'dovich效应对五年WMAP数据的贡献

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

Ricardo Genova-Santos, Fernando Atrio-Barandela, Jan Muecket, Jochen Klar

摘要:

利用Wilkinson微波各向异性探测器(WMAP)五年观测数据,研究了由温暖-热的星系际介质(WHIM)产生的运动学Sunyaev-Zel'dovich(kSZ)效应对宇宙微波背景(CMB)温度各向异性的贡献。我们探索的一致性LambdaCDM宇宙模型,有和没有这个kSZ的贡献,使用马尔可夫链蒙特卡罗算法。我们的模型需要一个额外的参数来描述这个新的组件。我们的结果表明,kSZ信号的加入改善了数据的拟合,而没有显著改变除Obh ^[2]外的最佳拟合宇宙学参数。这种改进局限于l>500的多极子。对于最佳拟合模型,该额外分量在l~450处达到峰值,振幅为129 μ K^2,占威尔金森微波各向异性探测器测得的总功率的3.1%。尽管如此,在2-sigma水平上,零kSZ贡献仍然与数据兼容。检测到的信号的一部分可能来自未掩蔽的点源和/或泊松分布的前景残差。一个统计上更重要的检测需要更广泛的频率覆盖范围和角分辨率即将到来的普朗克任务。

英文摘要:

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.

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