Scaling relations and mass bias in hydrodynamical f (R) gravity simulations of galaxy clusters
Scaling relations and mass bias in hydrodynamical f (R) gravity simulations of galaxy clusters
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DOI：
10.1093/mnras/stu332
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发表时间：
2014-05-01
影响因子：
4.8
通讯作者：
Springel, Volker
中科院分区：
文献类型：
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作者：
Arnold, Christian;Puchwein, Ewald;Springel, Volker
我们研究了变色龙型f (R)引力模型对星系团和星群性质的影响。我们的f (R)模拟也首次遵循簇内和群内介质的流体动力学。这使我们能够评估f (R)重力如何改变星团的x射线尺度关系，以及当重力的修改在确定中被忽略时，流体静力学和动力学质量估计是如何偏差的。我们发现，在f (R)重力下，低质量晕的速度色散和星系团内介质温度都增加了高达1/3，而在大质量天体中，这种差异消失了。跃迁的质量尺度取决于标量自由度的背景值f（R0）。温度和速度色散的这些变化改变了质量-温度和x射线亮度-温度的标度关系，并使不能明确说明修正重力的动态和流体静力质量估计偏向于更高的值。最近，普朗克合作组织发现，与弱透镜质量相比，x射线的相对增强。我们证明，这种偏移可以通过修正重力和相关的偏倚效应来解释，有趣的是，这些偏倚效应具有所需的大小。最后，我们发现在固定的星团质量下，亚晕的丰度仅受f (R)引力的微弱影响。
We investigate the impact of chameleon-type f (R) gravity models on the properties of galaxy clusters and groups. Our f (R) simulations follow for the first time also the hydrodynamics of the intracluster and intragroup medium. This allows us to assess how f (R) gravity alters the X-ray scaling relations of clusters and how hydrostatic and dynamical mass estimates are biased when modifications of gravity are ignored in their determination. We find that velocity dispersions and intracluster medium temperatures are both increased by up to 1/3 in f (R) gravity in low-mass haloes, while the difference disappears in massive objects. The mass scale of the transition depends on the background value f(R0) of the scalar degree of freedom. These changes in temperature and velocity dispersion alter the mass-temperature and X-ray luminosity-temperature scaling relations and bias dynamical and hydrostatic mass estimates that do not explicitly account for modified gravity towards higher values. Recently, a relative enhancement of X-ray compared to weak lensing masses was found by the Planck Collaboration. We demonstrate that an explanation for this offset may be provided by modified gravity and the associated bias effects, which interestingly are of the required size. Finally, we find that the abundance of subhaloes at fixed cluster mass is only weakly affected by f (R) gravity.