Models of Galaxy Clusters with Thermal Conduction
Models of Galaxy Clusters with Thermal Conduction
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DOI：
10.1086/344641
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发表时间：
2002-07
期刊：
影响因子：
--
通讯作者：
N. Zakamska;R. Narayan
中科院分区：
文献类型：
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作者：
N. Zakamska;R. Narayan
我们提出了一个简单的星系团热气体模型，假设流体静力学平衡和辐射冷却和热传导之间的能量平衡。对于A1795、A1835、A2199、A2390和RX J1347.5-1145这5个团簇，假设热导率κ约为Spitzer热导率的30%，模型能很好地描述电子密度和温度的径向分布。由于所需的κ与Narayan & Medvedev最近对湍流磁化等离子体的理论估计一致，我们认为基于传导的平衡模型对这些团簇是可行的。我们进一步表明，热气体是热稳定的，因为存在传导。对于其他五个星系团，A2052、A2597、Hydra A、Ser 159-03和3C 295，模型需要非物理性的大κ值来拟合数据。这些星系团必须有一些额外的热源，可能是一个活动星系核，因为所有的星系团在它们的中心都有强大的射电星系。我们认为，热传导，虽然在这些集群中不占主导地位，但可能发挥重要作用，防止气体变得热不稳定。
We present a simple model of hot gas in galaxy clusters, assuming hydrostatic equilibrium and energy balance between radiative cooling and thermal conduction. For five clusters, A1795, A1835, A2199, A2390, and RX J1347.5-1145, the model gives a good description of the observed radial profiles of electron density and temperature, provided that we take the thermal conductivity κ to be about 30% of the Spitzer conductivity. Since the required κ is consistent with the recent theoretical estimate of Narayan & Medvedev for a turbulent magnetized plasma, we consider a conduction-based equilibrium model to be viable for these clusters. We further show that the hot gas is thermally stable because of the presence of conduction. For five other clusters, A2052, A2597, Hydra A, Ser 159-03, and 3C 295, the model requires unphysically large values of κ to fit the data. These clusters must have some additional source of heat, possibly an active galactic nucleus, since all the clusters have strong radio galaxies at their centers. We suggest that thermal conduction, although not dominant in these clusters, may nevertheless play a significant role by preventing the gas from becoming thermally unstable.