Do the Electrons and Ions in X-Ray Clusters Share the Same Temperature?
Do the Electrons and Ions in X-Ray Clusters Share the Same Temperature?
复制标题
X射线簇中的电子和离子温度相同吗？
DOI：
10.1086/305007
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
A. Loeb
中科院分区：
文献类型：
--
作者：
D. Fox;A. Loeb
X射线团周围的维里化激波主要是加热离子，因为它们携带了下落气体的大部分动能。随后，离子通过库仑碰撞与电子分享它们的热能。我们量化的电子和离子之间的预期温度差作为半径和时间的函数，基于一个球形的自相似模型的气体吸积在一个Ω = 1，h50 = 1的宇宙中的集群。X射线温度TX = 4-10 × 107 K的团簇在半径为102 Mpc处的电子温度和离子温度有明显的差异。使用未来的X射线卫星（如Astro-E）的高分辨率光谱学可能能够从其X射线发射线的宽度确定星团内气体的离子温度，并将其与从自由-自由发射光谱推断的电子温度进行比较。这些温度之间的任何差异都可以用来确定自下落气体加入星团以来所经过的时间。
The virialization shock around an X-ray cluster primarily heats the ions, since they carry most of the kinetic energy of the infalling gas. Subsequently, the ions share their thermal energy with the electrons through Coulomb collisions. We quantify the expected temperature difference between the electrons and ions as a function of radius and time, based on a spherical self-similar model for the accretion of gas by a cluster in an Ω = 1, h50 = 1 universe. Clusters with X-ray temperatures TX = 4-10 × 107 K show noticeable differences between their electron and ion temperatures at radii ≳2 Mpc. High-resolution spectroscopy with future X-ray satellites such as Astro-E may be able to determine the ion temperature in intracluster gas from the width of its X-ray emission lines and compare it to the electron temperature as inferred from the free-free emission spectrum. Any difference between these temperatures can be used to date the period of time that has passed since the infalling gas joined the cluster.