Continuous Jets and Backflow Models for the Formation of W50/SS 433 in Magnetohydrodynamics Simulations
Continuous Jets and Backflow Models for the Formation of W50/SS 433 in Magnetohydrodynamics Simulations
复制标题
磁流体动力学模拟中形成 W50/SS 433 的连续射流和回流模型
DOI：
10.3847/1538-4357/abe5a1
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
T. Ohmura;K. Ono;H. Sakemi;Y. Tashima;R. Omae;M. Machida
中科院分区：
文献类型：
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作者：
T. Ohmura;K. Ono;H. Sakemi;Y. Tashima;R. Omae;M. Machida
W50/SS 433复合体的形成机制长期以来一直是个谜。我们提出了一种新的方案，在这种方案中，SS 433喷气式飞机本身形成了W50/SS 433系统。我们使用公共程序CANS+对两侧射流的传播进行了磁流体力学模拟。在以前的喷注研究中发现，当传播的喷流比周围的介质轻时，受冲击的等离子体会从喷嘴回流到核心。我们发现，早期的光喷流形态是球形的；后来，外壳和翅膀是由加宽的球形茧发展而来的。其形貌强烈地依赖于喷射射流与周围介质的密度比。同时，两侧射流的长度之比仅取决于周围介质的密度分布。我们还发现，大部分喷流动能在回流和束流相互作用形成的斜激波处耗散，而不是在喷流末端激波处耗散。斜激波的位置与W50的X射线和TeV伽马射线热点在空间上是一致的。
The formation mechanism of the W50/SS 433 complex has long been a mystery. We propose a new scenario in which the SS 433 jets themselves form the W50/SS 433 system. We carry out magnetohydrodynamics simulations of the propagation of two side jets using the public code CANS+. As found in previous jet studies, when the propagating jet is lighter than the surrounding medium, the shocked plasma flows back from the jet tip to the core. We find that the morphology of light jets is spheroidal at early times; afterward, the shell and wings are developed by the broadening spherical cocoon. The morphology depends strongly on the density ratio of the injected jet to the surrounding medium. Meanwhile, the ratio of the lengths of the two side jets depends only on the density profile of the surrounding medium. We also find that most of the jet kinetic energy is dissipated at the oblique shock formed by the interaction between the backflow and beam flow, rather than at the jet terminal shock. The position of the oblique shock is spatially consistent with the X-ray and TeV gamma-ray hotspots of W50.