Discovery of a New Fundamental Plane Dictating Galaxy Cluster Evolution from Gravitational Lensing
Discovery of a New Fundamental Plane Dictating Galaxy Cluster Evolution from Gravitational Lensing
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DOI：
10.3847/1538-4357/aab8fd
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发表时间：
2018-01
期刊：
影响因子：
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通讯作者：
Y. Fujita;K. Umetsu;E. Rasia;M. Meneghetti;M. Donahue;E. Medezinski;N. Okabe;M. Postman
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文献类型：
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作者：
Y. Fujita;K. Umetsu;E. Rasia;M. Meneghetti;M. Donahue;E. Medezinski;N. Okabe;M. Postman
在冷暗物质(CDM)宇宙学中，宇宙中的物体是在暗物质引力的影响下生长的。当暗物质晕通过引力崩塌形成时，星系团中的星系团内气体被加热。气体的势能通过这个过程转化为热能。然而，关于暗物质晕内部结构的形成和演化，这一过程和气体的热力学历史还没有得到明确的描述。在这里，我们证明了高质量星系团的观测碰撞数据位于其特征半径Rs、质量ms和X射线温度Tx的三维对数空间中的一个平面上，具有很小的正交散射。紧关联表明气体温度是在特定的团簇形成时间确定的，该时间编码为Rs和ms，平面相对于Tx∝ms/rS倾斜，这是简化维里平衡情况下预期的平面。我们发现，这种倾斜可以用相似解来解释，这表明星系团不是孤立的，而是通过外部环境的物质积累而持续增长的。数值模拟再现了观测到的平面及其角度。这一结果与代码中实施的气体物理无关，揭示了该平面的基本起源。
In cold dark-matter (CDM) cosmology, objects in the universe have grown under the effect of gravity of dark matter. The intracluster gas in a galaxy cluster was heated when the dark-matter halo formed through gravitational collapse. The potential energy of the gas was converted to thermal energy through this process. However, this process and the thermodynamic history of the gas have not been clearly characterized in connection with the formation and evolution of the internal structure of dark-matter halos. Here, we show that observational CLASH data of high-mass galaxy clusters lie on a plane in the three-dimensional logarithmic space of their characteristic radius rs, mass Ms, and X-ray temperature TX with a very small orthogonal scatter. The tight correlation indicates that the gas temperature was determined at a specific cluster formation time, which is encoded in rs and Ms. The plane is tilted with respect to TX ∝ Ms/rs, which is the plane expected in the case of simplified virial equilibrium. We show that this tilt can be explained by a similarity solution, which indicates that clusters are not isolated but continuously growing through matter accretion from their outer environments. Numerical simulations reproduce the observed plane and its angle. This result holds independently of the gas physics implemented in the code, revealing the fundamental origin of this plane.