Statistics of gravitational potential perturbations: A novel approach to deriving the X-ray temperature function
Statistics of gravitational potential perturbations: A novel approach to deriving the X-ray temperature function
复制标题
引力势扰动统计：一种推导 X 射线温度函数的新方法
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
M. Bartelmann
中科院分区：
文献类型：
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作者：
C. Angrick;M. Bartelmann
上下文虽然晕质量函数在理论上是宇宙学模型的一个非常敏感的度量，但暗物质晕的质量是定义不清的、全局的和不可观测的量。目标。我们认为，当地的，可观察到的数量，如星系团的X射线温度可以直接比较的理论预测，而无需调用群众。我们直接从引力势中高斯随机涨落的统计中导出X射线温度函数。方法.我们推导出的要求，他们属于线性崩溃的结构约束的潜在的最小值的丰度。然后，我们使用的球塌缩模型与线性非线性扰动，和维里定理转换潜在的深度温度。在推导中没有提到质量或其他全局量。结果应用适当的高通滤波器，从引力势中去除足够大的模式，我们得到一个X射线温度函数，与经典的Press-Schechter方法在相关的温度尺度上非常一致，但避免了测量质量的必要性。结论.这第一项研究表明，以及如何X射线温度函数的星系团可以解析导出，避免引入定义不清的全球量，如晕质量。这种方法将有助于减少观测到的星系团分布的分散性，从而减少从中得出的宇宙学结论。
Context. While the halo mass function is theoretically a very sensitive measure of cosmological models, masses of dark-matter halos are poorly defined, global, and unobservable quantities. Aims. We argue that local, observable quantities such as the X-ray temperatures of galaxy clusters can be directly compared to theoretical predictions without invoking masses. We derive the X-ray temperature function directly from the statistics of Gaussian random fluctuations in the gravitational potential. Methods. We derive the abundance of potential minima constrained by the requirement that they belong to linearly collapsed structures. We then use the spherical-collapse model to relate linear to non-linear perturbations, and the virial theorem to convert potential depths to temperatures. No reference is made to mass or other global quantities in the derivation. Results. Applying a proper high-pass filter that removes large enough modes from the gravitational potential, we derive an X-ray temperature function that agrees very well with the classical Press-Schechter approach on relevant temperature scales, but avoids the necessity of measuring masses. Conclusions. This first study shows that and how an X-ray temperature function of galaxy clusters can be analytically derived, avoiding the introduction of poorly defined global quantities such as halo masses. This approach will be useful for reducing scatter in observed cluster distributions and thus in cosmological conclusions drawn from them.