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arXiv 2109.03514astro-ph.HEastro-ph.GA
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相对论性喷流模拟中的射线追踪:磁场形态和电子标度关系的偏振研究

Ray-Tracing in Relativistic Jet Simulations: A Polarimetric Study of Magnetic Field Morphology and Electron Scaling Relations

Joana A. Kramer, Nicholas R. MacDonald

摘要:

从活动星系核(AGN)中心发出的喷流是宇宙中能量最高的天体之一。调查射流的同步辐射的形态如何取决于射流的相对论等离子体的磁性,这是数值模拟和观察到的相对论射流的偏振之间的比较的基础。通过使用3D相对论磁流体动力学(RMHD)射流模拟(计算使用PLUTO代码),我们研究如何射流的同步辐射取决于射流的磁场结构的形态。通过偏振辐射转移和射线跟踪(通过RADMC-3D代码)的应用程序,我们创建的射流的总强度,以及每个射流模拟的线性和圆偏振强度的合成无线电地图。特别是,我们创建合成射线跟踪图像的喷气机的偏振同步辐射时,喷气机进行了主要是极向,螺旋,和环形磁场。我们还探讨了几个标度关系,其中基本的电子幂律分布设置成正比:(i)射流的热等离子体密度,(ii)射流的内能密度,和(iii)射流的磁能密度。我们发现:(i)当磁场本质上是环形时,射流发射是边缘增亮的,而当磁场本质上是极向时,脊增亮,(ii)对于45°和5°倾角的环形磁场形态,圆偏振发射表现出负号和正号,(iii)当不考虑周围介质时,相对论性喷流的发射与不同的发射标度关系基本无关。

英文摘要:

The jets emanating from the centers of active galactic nuclei (AGN) are among the most energetic objects in the universe. Investigating how the morphology of the jet's synchrotron emission depends on the magnetic nature of the jet's relativistic plasma is fundamental to the comparison between numerical simulations and the observed polarization of relativistic jets. Through the use of 3D relativistic magnetohydrodynamic (RMHD) jet simulations (computed using the PLUTO code) we study how the jet's synchrotron emission depends upon the morphology of the jet's magnetic field structure. Through the application of polarized radiative transfer and ray-tracing (via the RADMC-3D code) we create synthetic radio maps of the jet's total intensity as well as the linearly and circularly polarized intensity for each jet simulation. In particular, we create synthetic ray-traced images of the jet's polarized synchrotron emission when the jet carries a predominantly poloidal, helical, and toroidal magnetic field. We also explore several scaling relations in which the underlying electron power-law distribution is set proportional to: (i) the jet's thermal plasma density, (ii) the jet's internal energy density, and (iii) the jet's magnetic energy density. We find that: (i) the jet emission is edge brightened when the magnetic field is toroidal in nature and spine brightened when the magnetic field is poloidal in nature, (ii) the circularly polarized emission exhibits both negative and positive signs for the toroidal magnetic field morphology at an inclination of 45° as well as 5°, and (iii) the relativistic jet's emission is largely independent of different emission scaling relations when the ambient medium is excluded.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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