论文标题
低X射线表面亮度群集：对$ M-T $和$ L-T $关系的散布的影响
Low X-ray surface brightness clusters: Implications on the scatter of the $M-T$ and $L-T$ relations
论文作者
论文摘要
我们的目的是研究一个小但定义明确的星系簇样本的比例关系，其中包括最近发现的X射线质量X射线的对象类别。这些簇的平均低X射线表面亮度，低气分，并且在X射线调查中的代表性不足（倍数为10倍）或在SZ调查中完全不存在。通过包含这些对象，我们发现温度质量关系具有前所未有的大散射，0.20+-0.03 DEX在固定质量下，温度范围允许的宽度，并且在该平面中簇的位置取决于其表面亮度。集群独立于它们的亮度，遵守相对紧密的亮度温度关系。我们解释了这两种关系周围散射的较大差异，因为X射线光度和温度是由来自小半径的光子（尤其是对于T）主导的，我们使用了300 kpc孔径半径），并且强烈影响气体热力学（例如，震动，凉爽的孔），而质量则由深色radii占主导地位。对于L500-T关系，我们测量2.0+-0.2的斜率。鉴于我们样本的特征，该值不受进化与斜率之间的共线性（退化）以及未检测到的人群的假设，这既影响X射线选定的样品的分析，因此可以盈利地用作参考和破坏X射线选定的S-Shamples的上述脱位。
We aim at studying scaling relations of a small but well defined sample of galaxy clusters that includes the recently discovered class of objects that are X-ray faint for their mass. These clusters have an average low X-ray surface brightness, a low gas fraction and are under-represented (by a factor of 10) in X-ray surveys or entirely absent in SZ surveys. With the inclusion of these objects, we find that the temperature-mass relation has an unprecedented large scatter, 0.20+-0.03 dex at fixed mass, as wide as allowed by the temperature range, and the location of a cluster in this plane depends on its surface brightness. Clusters obey a relatively tight luminosity-temperature relation independently of the their brightness. We interpret the wide difference in scatter around the two relations as due to the fact that X-ray luminosity and temperature are dominated by photons coming from small radii (in particular for T we used a 300 kpc aperture radius) and strongly affected by gas thermodynamics (e.g. shocks, cool-cores), whereas mass is dominated by dark matter at large radii. We measure a slope of 2.0+-0.2 for the L500-T relation. Given the characteristics of our sample, this value is free from the collinearity (degeneracy) between evolution and slope and from hypothesis on the undetected population, that both affect the analysis of X-ray selected samples, and can therefore be profitably used both as reference and to break the above degeneracy of X-ray selected-samples.
