Submitted to The Astrophysical Journal. Preprint typeset using L ATEX style emulateapj v. 04/03/99 A MAGNETICALLY-SWITCHED, ROTATING BLACK HOLE MODEL FOR THE PRODUCTION OF EXTRAGALACTIC RADIO JETS AND THE FANAROFF AND RILEY CLASS DIVISION
Submitted to The Astrophysical Journal. Preprint typeset using L ATEX style emulateapj v. 04/03/99 A MAGNETICALLY-SWITCHED, ROTATING BLACK HOLE MODEL FOR THE PRODUCTION OF EXTRAGALACTIC RADIO JETS AND THE FANAROFF AND RILEY CLASS DIVISION
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DOI：
10.1086/307671
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发表时间：
1998-10
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提出了一个模型，其中 Fanaroff 和 Riley (FR) I 类和 II 类河外喷流都是由旋转黑洞的能层中的磁化吸积盘日冕产生的。它采用了 Blandford-Payne 和 Blandford-Znajek 磁流体动力学机制的混合版本（类似于 Punsly-Coroniti 模型，增加了公制剪切驱动发电机）和磁性开关的通用形式，该开关被证明是爱丁顿光度的 MHD 模拟。虽然喷流是在能层吸积盘本身中产生的，但输出功率仍然是黑洞角动量的递增函数。为了获得足够高的自旋，黑洞会触发磁开关，产生高度相对论性、动能主导的喷流，而不是低自旋的磁能主导的喷流。在观测到的 FR 断裂功率下触发开关所需的日冕质量密度非常小（约 10-15 g cm-3），这意味着喷流材料的来源可能是一对等离子体或非常稀薄的电子-质子日冕，而不是主吸积盘本身。该模型解释了 FR I 和 II 源之间形态和马赫数的差异，以及观察到的大质量星系（包含更多大质量黑洞）在更高无线电功率下经历 FR I/II 转变的趋势。它还与扩展射电波瓣的能量含量一致，并解释了为什么由于黑洞自旋下降，FR II 源的空间密度应该比 FR I 源的空间密度演化得更快。提出了一种具体的观测测试来区分像这样的模型（其中 FR I/II 划分是由黑洞附近的过程产生的）和像 Bicknell 的模型（其中差异是由宿主星系的星际介质中的过程产生的）。如果当前模型是正确的，那么以 FR I 形态（而非光度）为特征的源中秒差距尺度喷流的集合平均速度应明显慢于具有 FR II 形态的源。该模型还表明，存在一群与螺旋星系或螺旋星系前相关的高红移、亚 mJy FR I 和 II 射电源，这些星系在黑洞形成时曾一度耀斑，但再也不会因合并而重新点燃。
A model is presented in which both Fanaroff and Riley (FR) class I and II extragalactic jets are produced by magnetized accretion disk coronae in the ergospheres of rotating black holes. It employs a hybrid version of the Blandford-Payne and Blandford-Znajek magnetohydrodynamic mechanisms (similar to the Punsly-Coroniti model, with the addition of a metric shear-driven dynamo) and a generalized form of the magnetic switch, which is shown to be the MHD analog of the Eddington luminosity. While the jets are produced in the ergospheric accretion disk itself, the output power still is an increasing function of the black hole angular momentum. For high enough spin, the black hole triggers the magnetic switch, producing highly relativistic, kinetic energy-dominated jets instead of magnetic energy-dominated jets for lower spin. The coronal mass densities needed to trigger the switch at the observed FR break power are quite small (~10-15 g cm-3), implying that the source of the jet material may be either a pair plasma or very tenuous electron-proton corona, not the main accretion disk itself. The model explains the differences in morphology and Mach number between FR I and II sources and the observed trend for massive galaxies (which contain more massive black holes) to undergo the FR I/II transition at higher radio power. It also is consistent with the energy content of extended radio lobes and explains why, because of black hole spin-down, the space density of FR II sources should evolve more rapidly than that of FR I sources. A specific observational test is proposed to distinguish between models like this one, in which the FR I/II division arises from processes near the black hole, and models like Bicknell's, in which the difference is produced by processes in the host galaxy's interstellar medium. If the present model is correct, then the ensemble average speed of parsec-scale jets in sources distinguished by their FR I morphology (not luminosity) should be distinctly slower than that for sources with FR II morphology. The model also suggests the existence of a population of high-redshift, sub-mJy FR I and II radio sources associated with spiral or prespiral galaxies that flared once when their black holes were formed but were never again rekindled by mergers.