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星系团：一个新的观察扩散重子抵抗暗物质引力的方法

Galaxy Clusters, a Novel Look at Diffuse Baryons Withstanding Dark Matter Gravity

A. Cavaliere, A. Lapi, R. Fusco-Femiano

备注：
13 pages, 8 figures, uses RevTeX4 + emulateapj.cls and apjfonts.sty. Typos corrected. Accepted by ApJ
发表信息：
Astrophys. J.698:580, 2009; Astrophys.J.698:580-593,2009
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摘要：

团内等离子体（ICP）和引力主导的暗物质（DM）的平衡由流体静力学和Jeans方程控制。金斯将DM“熵”设为K ~ r^α，α~ 1.25 - 1.3，从集团应用到富星系团，得到了我们的径向α分布。在ICP中，熵运行k（r）主要是由激波形成的，由气体在星系团边界的超音速吸积稳定地设定，并由合并事件或活动星系核间歇地从中心驱动;由此产生的平衡由构成我们的ICP超模型的精确而简单的形式描述。通过几个参数，这精确地代表了密度n（r）和温度T（r）的运行，正如最近的X射线数据所要求的，冷核（CC）和非冷核（NCC）星系团的表面亮度和光谱学;前者由一个中间温度峰标记，其位置从富星系团到集团预测。超级模型将n（r）和T（r）的内部运行反向联系起来，并强调了它们的中心标度（熵为n_c ~ k_c^-1和T_c ~ k_c ^0. 35），从而得到辐射冷却时间t_c ~ 0. 3（k_c/15 keV cm ^2）^1. 2 Gyr。我们讨论的稳定性的中心值集中在CC和NCC集群。从超模型出发，我们导出了经典的多方β模型和“镜像”模型，它们分别适用于NCC和CC团簇，其中T（r）~ σ^2（r）是它们的极限情况;这些结果突出了ICP温度T（r）如何倾向于反映DM速度色散σ^2（r），使之远离熵注入。最后，我们将讨论超级模型如何将X射线和引力透镜观测的信息联系起来。

英文摘要：

[abridged] The equilibria of the intracluster plasma (ICP) and of the gravitationally dominant dark matter (DM) are governed by the hydrostatic and the Jeans equation. Jeans, with the DM `entropy' set to K ~ r^αand α~ 1.25 - 1.3 applying from groups to rich clusters, yields our radial α-profiles. In the ICP the entropy run k(r) is mainly shaped by shocks, as steadily set by supersonic accretion of gas at the cluster boundary, and intermittently driven from the center by merging events or by AGNs; the resulting equilibrium is described by the exact yet simple formalism constituting our ICP Supermodel. With a few parameters, this accurately represents the runs of density n(r) and temperature T(r) as required by recent X-ray data on surface brightness and spectroscopy for both cool core (CC) and non cool core (NCC) clusters; the former are marked by a middle temperature peak, whose location is predicted from rich clusters to groups. The Supermodel inversely links the inner runs of n(r) and T(r), and highlights their central scaling with entropy n_c ~ k_c^-1 and T_c ~ k_c^0.35, to yield radiative cooling times t_c ~ 0.3 (k_c/15 keV cm^2)^1.2 Gyr. We discuss the stability of the central values so focused either in CC and NCC clusters. From the Supermodel we derive as limiting cases the classic polytropic β-models, and the `mirror' model with T(r) ~ σ^2(r) suitable for NCC and CC clusters, respectively; these highlight how the ICP temperature T(r) tends to mirror the DM velocity dispersion σ^2(r) away from entropy injections. Finally, we discuss how the Supermodel connects information derived from X-ray and gravitational lensing observations.

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