Hot bubbles from active galactic nuclei as a heat source in cooling-flow clusters
Hot bubbles from active galactic nuclei as a heat source in cooling-flow clusters
复制标题
来自活动星系核的热气泡作为冷却流星团的热源
DOI：
10.1038/nature00857
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发表时间：
2002
期刊：
影响因子：
64.8
通讯作者：
C. Kaiser
中科院分区：
文献类型：
--
作者：
M. Brüggen;C. Kaiser
炽热的X射线等离子体弥漫在星系团中。X射线表面亮度经常在星团中心附近显示出一个峰值，这与气体熵的下降相一致。这被认为是“冷却流”的证据，即气体通过辐射其能量而冷却，然后福尔斯落到中心。对这种冷气体的研究表明，其沉积速率明显低于预期，表明质量沉积速率远低于预期。然而，大多数具有冷却流的星系团在其中心也有一个活动星系核。这些活跃的星系核可以膨胀热等离子体的大气泡，随后通过集群“大气”上升，从而搅拌冷却气体并增加能量。在这里，我们报告高分辨率的流体动力学模拟表明，浮力气泡增加冷却时间在集群的内部区域，显着减少冷气体的沉积。
Hot, X-ray-emitting plasma permeates clusters of galaxies. The X-ray surface brightness often shows a peak near the centre of the cluster that is coincident with a drop in the entropy of the gas. This has been taken as evidence for a ‘cooling flow’, where the gas cools by radiating away its energy, and then falls to the centre. Searches for this cool gas have revealed significantly less than predicted, indicating that the mass deposition rate is much lower than expected. Most clusters with cooling flows, however, also host an active galactic nucleus at their centres. These active galactic nuclei can inflate large bubbles of hot plasma that subsequently rise through the cluster ‘atmosphere’, thus stirring the cooling gas and adding energy. Here we report highly resolved hydrodynamic simulations which show that buoyant bubbles increase the cooling time in the inner regions of clusters and significantly reduce the deposition of cold gas.