Feedback under the microscope - II. Heating, gas uplift and mixing in the nearest cluster core
Feedback under the microscope - II. Heating, gas uplift and mixing in the nearest cluster core
复制标题
显微镜下的反馈 - II。
DOI：
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
G. Taylor
中科院分区：
文献类型：
--
作者：
N. Werner;A. Simionescu;E. Million;S. Allen;P. Nulsen;A. V. D. Linden;S. Hansen;H. Boehringer;E. Churazov;A. Fabian;W. Forman;C. Jones;J. Sanders;G. Taylor
利用深度（574 ks）Chandra数据、XMM-Newton高分辨光谱和光学Hα+[N II]图像，研究了M87中多相等离子体的性质和空间分布。我们的研究结果提供了直接的观测证据，“无线电模式”的活动星系核（AGN）的反馈在行动中，剥离其最低熵气体的中央星系，从而防止星星的形成。这些低熵气体被急剧上升的相对论等离子体夹带并抬升，形成长长的“手臂”。许多论据表明，这些手臂的方向在我们视线的15°-30°范围内。上升的气体在武器的质量是在近似球对称的3.8千秒差距核心的气体质量相媲美，表明活动星系核有一个深刻的影响，其周围环境。M87中最冷的X射线发射气体的温度约为0.5 keV，在空间上与Hα+[N II]星云重合，形成了一种多相介质，其中较冷的气相排列在磁化的细丝中。我们把强大的上限0.06兆年-1（95%的置信度）的等离子体辐射冷却量从0.5至0.25千电子伏，并表明，一个统一的，体积平均的加热机制不能阻止冷气体进一步冷却。M87中所有明亮的Hα细丝都出现在300万年前的激波阵面的下游区域，半径小于0.6弧分。我们认为，冲击诱导剪切周围的细丝，从而促进混合的冷气体与周围的热的集群内介质（ICM）通过不稳定性。通过使热的热粒子与冷的线发射气体接触，混合可以提供解释所观察到的光谱所需的能量和电离粒子。此外，最冷的X射线发射等离子体与冷的光学线发射惰性气体的混合促进了两相之间的有效传导，允许非辐射冷却，这可以解释温度低于0.5 keV的X射线气体的缺乏。
Using a combination of deep (574 ks) Chandra data, XMM-Newton high-resolution spectra and optical Hα+[N II] images, we study the nature and spatial distribution of the multi-phase plasma in M87. Our results provide direct observational evidence of 'radio-mode' active galactic nuclei (AGN) feedback in action, stripping the central galaxy of its lowest entropy gas and therefore preventing star formation. This low entropy gas was entrained with and uplifted by the buoyantly rising relativistic plasma, forming long 'arms'. A number of arguments suggest that these arms are oriented within 15°-30° of our line-of-sight. The mass of the uplifted gas in the arms is comparable to the gas mass in the approximately spherically symmetric 3.8 kpc core, demonstrating that the AGN has a profound effect on its immediate surroundings. The coolest X-ray emitting gas in M87 has a temperature of ~0.5 keV and is spatially coincident with Hα+[N II] nebulae, forming a multi-phase medium where the cooler gas phases are arranged in magnetized filaments. We place strong upper limits of 0.06 M ⊙ yr -1 (at 95 per cent confidence) on the amount of plasma cooling radiatively from 0.5 to 0.25 keV and show that a uniform, volume-averaged heating mechanism could not be preventing the cool gas from further cooling. All of the bright Hα filaments in M87 appear in the downstream region of the <3 Myr old shock front, at smaller radii than ~0.6 arcmin. We suggest that shocks induce shearing around the filaments, thereby promoting mixing of the cold gas with the ambient hot intra-cluster medium (ICM) via instabilities. By bringing hot thermal particles into contact with the cool, line-emitting gas, mixing can supply the power and ionizing particles needed to explain the observed optical spectra. Furthermore, mixing of the coolest X-ray emitting plasma with the cold optical line-emitting filamentary gas promotes efficient conduction between the two phases, allowing non-radiative cooling which could explain the lack of X-ray gas with temperatures under 0.5 keV.
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长蛇座 A 星系团的大规模激波
影响因子：
6.5
作者：
Simionescu;Roediger;Nulsen;P. E. J;Brüggen;Forman;Böhringer;H.Werner;Finoguenov
通讯作者：
Finoguenov
影响因子：
6.5
作者：
A. Simionescu;N. Werner;A. Finoguenov;H. Böhringer;M. Brüggen
通讯作者：
A. Simionescu;N. Werner;A. Finoguenov;H. Böhringer;M. Brüggen
用 XMM-Newton 观测到的 M87 的气体气氛
DOI：
10.1051/0004-6361:20066650
发表时间：
2007
期刊：
影响因子：
--
作者：
Simionescu;Böhringer;Brüggen;Finoguenov
通讯作者：
Finoguenov
影响因子：
6.5
作者：
A. Simionescu;N. Werner;H. Böhringer;J. Kaastra;A. Finoguenov;M. Brüggen;P. Nulsen
通讯作者：
A. Simionescu;N. Werner;H. Böhringer;J. Kaastra;A. Finoguenov;M. Brüggen;P. Nulsen