A theoretical model of Fanaroff-Riley I jets
A theoretical model of Fanaroff-Riley I jets
复制标题
Fanaroff-Riley I 射流的理论模型
DOI：
10.1007/bf00653299
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
S. Komissarov
中科院分区：
文献类型：
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作者：
S. Komissarov
本文根据Fanaroff-RückI类河外射电源喷流是由相对论和非相对论等离子体组成的低马赫数超音速湍流的观点，建立了一个流场模型。本文描述了定常射流的数值计算，这些射流的物理参数对应于FR-I射流的速度、密度、马赫数、扩散率、相对论颗粒压力和功率等观测约束。研究了椭圆星系典型大气中喷流的传播特性。结果表明，尽管基本减速，射流运输散装运动动能几乎没有损失。喷流的低密度热等离子体（约10− 6 cm −3）导致喷流内部的法拉第旋转可以忽略不计。沿射流沿着的质量通量只能用于研究外部气体的卷入，而不能用于研究中心“原动机”的“排放”。射流通常可细分为提供主要能量传输的超音速快速核心和提供沿射流沿着的主要质量传递的跨音速慢速鞘。射电亮度的变化沿着喷流的估计。我们的结论是，相对论电子的有效再加速需要解释所观察到的FR-I喷流的亮度分布。在星系的X射线大气中的径向压力梯度的值和喷流变暗的速率之间的相关性是预期的。
A fluid model of the jets in Fanaroff-Raily I class extragalactic radio sources based on the idea that they are turbulent low Mach number supersonic flows consisting of relativistic and nonrelativistic plasma has been developed. Numerical calculations of steady jets whose physical parameters correspond to observational constraints on velocity, density, Mach number, spreading rate, relativistic particles pressure and power of FR-I jets are described. The properties of the jets, propagating through typical atmosphere of elliptical galaxy are studied. It is shown that, in spite of essential deceleration, the jets transport bulk motion kinetic energy almost without losses. The low densities of the jets thermal plasma (∼10−6cm−3) result in negligible Faraday rotation inside the jets. Mass fluxes along the jets may be used only to study the external gas entraiment but not the ‘discharge’ of central ‘prime mover’. The jets can be conventionally subdivided into a supersonic fast core providing the main energy transport and a transonic slow sheath providing the main mass transfer along the jets. Variations of radio brightness along the jets are estimated. it is concluded that an effective re-acceleration of relativistic electrons is required to explain the observed brightness distribution of FR-I jets. A correlation between the value of the radial pressure gradient in the X-ray atmosphere of the galaxy and the rate of jet darkening is expected.