星系团中X射线空洞的形成

Formation of the X-ray Cavities in Galaxy Clusters

星系团中的一小部分活动星系核周围存在巨大的X射线空洞,X射线观测发现这些空洞的内能为10^(48)~10^(55)J。一般认为这些空洞的能量来自活动星系核的喷流。MS 0735+7421是已知内能最高的一个X射线空洞,包含的能量为10^(55)J,由观测数据估计出其中央黑洞质量为5×10^(9)M_(⊙),射电观测发现其目前的喷流活动性较弱,喷流的活动时间大约为10^(8)a。利用最新建立的随机吸积-喷流模型对该源X射线空洞的形成过程进行研究,发现随机吸积产生的喷流能很好地解释空洞总能量及中央黑洞质量等重要观测现象。

The giant X-ray cavities,with typical internal energy around 10^(49)~10^(55) J have been found around some active galactic nuclei(AGNs)in galaxy cluster.Generally,these cavities are thought to be powered by the strong jets of AGNs.MS 0735+7421 hosts the most energetic AGN outburst known with the total energy around 10^(55) J.Observations show that the central black mass is about 5×10^(9)M_(⊙) and the timespan of the jet activity is about 10^(8) a.Recent radio data revealed that the jet activity of this source is relatively weak.In this work,we study the formation of this giant X-ray cavity using a model combining jet with chaotic accretion process.The total energy of the cavity and the mass of the central super massive black hole derived in our work are qualitatively consistent with the observational data.