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arXiv 0909.1282astro-ph.CO
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团簇和群中AGN外流的三维数值模拟

3D Numerical Simulations of AGN Outflows in Clusters and Groups

M. Gaspari, C. Melioli, F. Brighenti, A. D'Ercole

摘要:

我们计算了从活动星系核中心流出的喷流的三维气体动力学模型,这些喷流携带质量和能量到星系团和星系群中的热气体。这些流动有许多有吸引力的属性,解决冷却流问题:为什么热气体的温度和密度分布类似于冷却流,但没有显示出冷却到低温的光谱证据。亚相对论射流,描述了几个参数,被认为是激活时,气体流向或冷却附近的中央SMBH。使用富聚类(A1795)的近似模型,(2A 0336+096)和一组(NGC 5044),我们表明,中等机械效率的质量携带射流($\sim10^{-3}$)可以将许多Gyr的整体冷却速率降低到X-光谱所暗示的低值或以下,同时保持$T$和$ρ$分布与观察到的分布相似,至少在集群中。集团更敏感的活动星系核加热和极端的时间变化,在这两个配置文件。最后,反馈的不稳定性产生了多代X射线腔,类似于英仙座星系团和其他地方观察到的。因此,我们还研究了ICM中浮力气泡和弱冲击的形成,以及SNIa和恒星风注入金属。

英文摘要:

We compute 3D gasdynamical models of jet outflows from the central AGN, that carry mass as well as energy to the hot gas in galaxy clusters and groups. These flows have many attractive attributes for solving the cooling flow problem: why the hot gas temperature and density profiles resemble cooling flows but show no spectral evidence of cooling to low temperatures. Subrelativistic jets, described by a few parameters, are assumed to be activated when gas flows toward or cools near a central SMBH. Using approximate models for a rich cluster (A1795), a poor cluster (2A 0336+096) and a group (NGC 5044), we show that mass-carrying jets with intermediate mechanical efficiencies ($\sim10^{-3}$) can reduce for many Gyr the global cooling rate to or below the low values implied by X-spectra, while maintaining $T$ and $ρ$ profiles similar to those observed, at least in clusters. Groups are much more sensitive to AGN heating and present extreme time variability in both profiles. Finally, the intermittency of the feedback generates multiple generations of X-ray cavities similar to those observed in Perseus cluster and elsewhere. Thus we also study the formation of buoyant bubbles and weak shocks in the ICM, along with the injection of metals by SNIa and stellar winds.

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