X-Ray Supercavities in the Hydra A Cluster and the Outburst History of the Central Galaxy’s Active Nucleus
X-Ray Supercavities in the Hydra A Cluster and the Outburst History of the Central Galaxy’s Active Nucleus
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DOI：
10.1086/512767
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发表时间：
2006-12
期刊：
影响因子：
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通讯作者：
M. Wise;M. Wise;B. McNamara;B. McNamara;P. Nulsen;P. Nulsen;John C. Houck;L. David
中科院分区：
文献类型：
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作者：
M. Wise;M. Wise;B. McNamara;B. McNamara;P. Nulsen;P. Nulsen;John C. Houck;L. David
一张227 ks的钱德拉X射线图像显示了水螅A星系团中的热等离子体，揭示了一个广泛的空腔系统。该系统是由中央星系核在过去的200-500百万年中持续流出或一系列爆发而形成的。这些空洞已经取代了中心星系半径300千秒差距内10%的等离子体，在热气中形成了瑞士奶酪般的拓扑结构。表面亮度的衰减与天空平面40°内的空洞一致。外流已经向上沉积了1061尔格进入团簇气体，其中大部分被推进到内部~100 kpc冷却区之外。在这段时间内，超大质量黑洞以大约0.1-0.25 M yr-1的速率吸积，这是~109 M黑洞的爱丁顿速率的一小部分，但大大大于邦迪速率。考虑到之前在长蛇座A中存在冷气体环核盘的证据，这些结果与活动星系核主要由下落的冷气体提供动力的说法一致。腔系统被330 MHz的无线电发射完全遮蔽。这种低频同步辐射可能是X射线空腔的一个很好的替代品，因此也是超大质量黑洞释放的总能量的一个很好的替代品。
A 227 ks Chandra X-ray image of the hot plasma in the Hydra A cluster has revealed an extensive cavity system. The system was created by a continuous outflow or a series of bursts from the nucleus of the central galaxy over the past 200-500 Myr. The cavities have displaced 10% of the plasma within a 300 kpc radius of the central galaxy, creating a swiss-cheese-like topology in the hot gas. The surface brightness decrements are consistent with empty cavities oriented within 40° of the plane of the sky. The outflow has deposited upward of 1061 ergs into the cluster gas, most of which was propelled beyond the inner ~100 kpc cooling region. The supermassive black hole has accreted at a rate of approximately 0.1-0.25 M☉ yr-1 over this time frame, which is a small fraction of the Eddington rate of a ~109 M☉ black hole, but is dramatically larger than the Bondi rate. Given the previous evidence for a circumnuclear disk of cold gas in Hydra A, these results are consistent with the AGN being powered primarily by infalling cold gas. The cavity system is shadowed perfectly by 330 MHz radio emission. Such low-frequency synchrotron emission may be an excellent proxy for X-ray cavities and thus the total energy liberated by the supermassive black hole.