The Birmingham–CfA cluster scaling project – II. Mass composition and distribution
The Birmingham–CfA cluster scaling project – II. Mass composition and distribution
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DOI：
10.1046/j.1365-2966.2003.07040.x
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发表时间：
2003-07
影响因子：
4.8
通讯作者：
A. Sanderson;A. Sanderson;T. Ponman
中科院分区：
文献类型：
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作者：
A. Sanderson;A. Sanderson;T. Ponman
我们研究了66个维里化系统中重子和非重子质量分量的空间分布。我们使用X射线测量来确定星系际介质的反投影温度和密度结构，并利用这些来绘制潜在的引力势。此外，我们已经测量了这个样本的一个子集，跨越二十多年的质量星系光度的空间分布。通过这种结合X射线/光学研究，我们研究了重子的标度特性，并解决了星系群和星系团中的质量与光（M/L）比问题。我们测量的中值质光比为249 h 70（M/L）O。在静止坐标系B J带中，与基于X射线确定的质量的其他测量结果良好一致。M/L没有随X射线温度变化的趋势，质量增加的速度也没有明显快于光度的趋势：M L 1。08英尺0英寸。12 B J.这意味着星星的形成效率没有显著的变化，这表明气体冷却不能在群体中大大增强，除非它退出形成重子暗物质。相应地，我们的研究结果表明，非引力加热必须发挥了重要作用，在建立观察到的偏离自相似性在低质量系统。我们的样品的重子分数中值为0.162 h-3/270，这使得我们可以将宇宙学物质密度的上限设定为Ω m ≤ 0.27 h-170，这与WMAP的最新结果非常一致。我们发现的证据表明，一个系统的趋势，更高的中心密度浓度在最冷的晕，早期形成时代的指示和分层形成模型相一致。
We investigate the spatial distribution of the baryonic and non-baryonic mass components in a sample of 66 virialized systems. We have used X-ray measurements to determine the deprojected temperature and density structure of the intergalactic medium and have employed these to map the underlying gravitational potential. In addition, we have measured the deprojected spatial distribution of galaxy luminosity for a subset of this sample, spanning over two decades in mass. With this combined X-ray/optical study, we examine the scaling properties of the baryons and address the issue of mass-to-light (M/L) ratio in groups and clusters of galaxies. We measure a median mass-to-light ratio of 249 h 7 0 (M/L) O . in the rest frame B J band, in good agreement with other measurements based on X-ray determined masses. There is no trend in M/L with X-ray temperature and no significant trend for mass to increase faster than luminosity: M L 1 . 0 8 ′ 0 . 1 2 B J . This implied lack of significant variation in star formation efficiency suggests that gas cooling cannot be greatly enhanced in groups, unless it drops out to form baryonic dark matter. Correspondingly, our results indicate that non-gravitational heating must have played a significant role in establishing the observed departure from self-similarity in low-mass systems. The median baryon fraction for our sample is 0.162 h - 3 / 2 7 0 , which allows us to place an upper limit on the cosmological matter density, Ω m ≤ 0.27 h - 1 7 0 , in good agreement with the latest results from WMAP. We find evidence of a systematic trend towards higher central density concentration in the coolest haloes, indicative of an early formation epoch and consistent with hierarchical formation models.