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由S-Z测量得到的CMB温度的红移依赖性

Redshift Dependence of the CMB Temperature from S-Z Measurements

G. Luzzi, M. Shimon, L. Lamagna, Y. Rephaeli, M. De Petris, A. Conte, S. De Gregori, E. S. Battistelli

备注：
Accepted for publication in ApJ
发表信息：
Astrophys.J.705:1122-1128,2009
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摘要：

通过对13个团簇的S-Z效应的多频测量，我们确定了红移在0.023-0.546范围内的CMB温度$T(z)$。我们提取了红移标度$T(z)=T_{0}(1+z)^{1-α}$中的参数$α$，将标准模型（$α=0$）的预言与其他一些宇宙学模型中的非绝热演化预言进行了对比.统计分析基于两种主要方法：使用S-Z强度变化的比率，$ΔI$，从而利用比率对IC气体性质的弱依赖性，以及直接使用$ΔI$测量。在前一种方法中，这些量对汤姆逊光学厚度和气体温度的依赖性仅为二阶。在第二种方法中，我们边缘化了这些量，这些量在强度变化中表现为一阶。边缘化本身以两种方式完成-通过直接积分和通过蒙特卡洛马尔可夫链方法。采用这些不同的方法，我们得到了两组结果是一致的$α=0$，与标准模型的预测。

英文摘要：

We have determined the CMB temperature, $T(z)$, at redshifts in the range 0.023-0.546, from multi-frequency measurements of the S-Z effect towards 13 clusters. We extract the parameter $α$ in the redshift scaling $T(z)=T_{0}(1+z)^{1-α}$, which contrasts the prediction of the standard model ($α=0$) with that in non-adiabatic evolution conjectured in some alternative cosmological models. The statistical analysis is based on two main approaches: using ratios of the S-Z intensity change, $ΔI$, thus taking advantage of the weak dependence of the ratios on IC gas properties, and using directly the $ΔI$ measurements. In the former method dependence on the Thomson optical depth and gas temperature is only second order in these quantities. In the second method we marginalize over these quantities which appear to first order in the intensity change. The marginalization itself is done in two ways - by direct integrations, and by a Monte Carlo Markov Chain approach. Employing these different methods we obtain two sets of results that are consistent with $α=0$, in agreement with the prediction of the standard model.

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