Partitioning the Outburst Energy of a Low Eddington Accretion Rate AGN at the Center of an Elliptical Galaxy: The Recent 12 Myr History of the Supermassive Black Hole in M87
Partitioning the Outburst Energy of a Low Eddington Accretion Rate AGN at the Center of an Elliptical Galaxy: The Recent 12 Myr History of the Supermassive Black Hole in M87
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DOI：
10.3847/1538-4357/aa70e4
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发表时间：
2017-05
期刊：
影响因子：
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通讯作者：
W. Forman;E. Churazov;Christine Jones;S. Heinz;R. Kraft;A. Vikhlinin
中科院分区：
文献类型：
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作者：
W. Forman;E. Churazov;Christine Jones;S. Heinz;R. Kraft;A. Vikhlinin
M87是室女座星系团中心的活跃星系，是研究超大质量黑洞（SMBH）与高温、富含气体环境相互作用的理想对象。钱德拉对M87的深层观测显示出一个近似圆形的激波阵面（投影半径为13 kpc），由中心空腔（充满相对论性射电等离子体的SMBH）的膨胀驱动，投影半径为1.9 kpc。我们结合联合收割机的X射线和射电观测M87的冲击模型，推导出的属性的爆发，创造了13千秒差距的冲击。该模型的主要约束条件是：（1）测量的马赫数（M = 1.2），（2）13 kpc激波的半径，（3）作为活塞驱动激波的中心空腔/气泡（射电明亮茧）的观测尺寸。我们发现，一个大约在1200万年前开始并持续了1200万年的105 × 1057尔格的爆发符合所有的约束条件。在这个模型中，当冲击波膨胀时，它携带了大约22%的能量。剩余的约80%的突出能量可用于加热核心气体。超过一半的总爆发能量最初进入中央气泡的焓，无线电茧。当浮力气泡上升时，它的大部分能量被转移到周围的热气体中。对于一个大约1200万年（爆发的年龄）的爆发重复率，80%的爆发能量足以平衡辐射冷却。
M87, the active galaxy at the center of the Virgo cluster, is ideal for studying the interaction of a supermassive black hole (SMBH) with a hot, gas-rich environment. A deep Chandra observation of M87 exhibits an approximately circular shock front (13 kpc radius, in projection) driven by the expansion of the central cavity (filled by the SMBH with relativistic radio-emitting plasma) with projected radius ∼1.9 kpc. We combine constraints from X-ray and radio observations of M87 with a shock model to derive the properties of the outburst that created the 13 kpc shock. Principal constraints for the model are (1) the measured Mach number (M ∼ 1.2), (2) the radius of the 13 kpc shock, and (3) the observed size of the central cavity/bubble (the radio-bright cocoon) that serves as the piston to drive the shock. We find that an outburst of ∼5 × 1057 erg that began about 12 Myr ago and lasted ∼2 Myr matches all the constraints. In this model, ∼22% of the energy is carried by the shock as it expands. The remaining ∼80% of the outburst energy is available to heat the core gas. More than half the total outburst energy initially goes into the enthalpy of the central bubble, the radio cocoon. As the buoyant bubble rises, much of its energy is transferred to the ambient thermal gas. For an outburst repetition rate of about 12 Myr (the age of the outburst), 80% of the outburst energy is sufficient to balance the radiative cooling.