STIRRING UP THE POT: CAN COOLING FLOWS IN GALAXY CLUSTERS BE QUENCHED BY GAS SLOSHING?
STIRRING UP THE POT: CAN COOLING FLOWS IN GALAXY CLUSTERS BE QUENCHED BY GAS SLOSHING?
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搅动锅子：星系团中的冷却流可以通过气体晃动来熄灭吗？
DOI：
10.1088/0004-637x/717/2/908
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Nh
中科院分区：
文献类型：
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作者：
J. Zuhone;M. Markevitch;R. Observatory;H. C. F. Astrophysics;Cambridge;Ma;D. O. Physics;Astronomy;Wilder Lab;Dartmouth College;Hanover;Nh
星系簇的X射线观察表明，表面亮度和温度中存在边缘，称为“冷锋”。群集的重力中的气体可以通过使用高分辨率的N-Body/Eulerian流体动力学模拟来使群集核心的热量来源。在与亚截面的合并中，仿真的群集包括与气体和无气体的合并场景。如果有足够的灾难，则促进热量流入群集。在粘稠的情况下，将簇核的熵地板几乎增加，如果ICM是粘性的，则将气体与不同的熵的混合得到改善，因此在模拟中减少了热量。包括，我们发现，尽管有时会发生冷却流的发展，但倾斜可以防止芯子在核心中的大量堆积，以便在小扰动的顺序上进行小小的干扰，如果重复遇到的子观察器，则可以与几个小扰动。如观察到的那样，维持中心核心气体的晃动，该过程可以为核心提供相对稳定的热源，这可以帮助防止明显的冷却流。
X-ray observations of clusters of galaxies reveal the presence of edges in surface brightness and temperature, known as “cold fronts.” In relaxed clusters with cool cores, these commonly observed edges have been interpreted as evidence for the “sloshing” of the core gas in the cluster's gravitational potential. Such sloshing may provide a source of heat to the cluster core by mixing hot gas from the cluster outskirts with the cool-core gas. Using high-resolution N-body/Eulerian hydrodynamic simulations, we model gas sloshing in galaxy clusters initiated by mergers with subclusters. The simulations include merger scenarios with gas-filled and gasless subclusters. The effect of changing the viscosity of the intracluster medium is also explored, but heat conduction is assumed to be negligible. We find that sloshing can facilitate heat inflow to the cluster core, provided that there is a strong enough disturbance. Additionally, sloshing redistributes the gas in the cluster core, causing the gas to expand and decreasing the efficiency of radiative cooling. In adiabatic simulations, we find that sloshing can raise the entropy floor of the cluster core by nearly an order of magnitude in the strongest cases. If the ICM is viscous, the mixing of gases with different entropies is decreased and consequently the heat flux to the core is diminished. In simulations where radiative cooling is included, we find that although eventually a cooling flow develops, sloshing can prevent the significant buildup of cool gas in the core for times on the order of a Gyr for small disturbances and a few Gyr for large ones. If repeated encounters with merging subclusters sustain the sloshing of the central core gas, as is observed, this process can provide a relatively steady source of heat to the core, which can help prevent a significant cooling flow.