Does the plasma composition affect the long-term evolution of relativistic jets?
Does the plasma composition affect the long-term evolution of relativistic jets?
复制标题
等离子体成分是否影响相对论性喷流的长期演化？
DOI：
10.1046/j.1365-8711.2002.05210.x
复制
发表时间：
2001
影响因子：
4.8
通讯作者：
I. D. A. D. Andalucia
中科院分区：
文献类型：
--
作者：
L. Scheck;M. Aloy;J. Martí;J. Gómez;E. M. M. F. Astrophysik;D. Valencia;I. D. A. D. Andalucia
我们研究了河外喷流的物质含量对其形态、动力学和发射特性的影响。为此目的，我们考虑的喷流的成分极其不同，包括纯轻子和重子等离子体。我们的工作是基于二维相对论流体动力学模拟的长期演变的强大的河外喷流传播到一个均匀的环境。模拟中使用的状态方程考虑了电子、质子和电子-正电子对的任意混合。利用流体动力学模型，我们还计算了合成射电图和热韧致辐射的X射线发射从他们的腔。
虽然有一个大约三个数量级的差异，在由模拟射流膨胀的空腔的温度，我们发现，无论是形态和动力学行为几乎是独立的假设组成的射流。它们的演变分为两个不同的时期。在第一个过程中，多维效应是不重要的，射流弹道传播。第二个时期开始时，第一个较大的涡流产生附近的喷射头，导致光束横截面增加和射流减速。茧和空洞的演化符合一个简单的理论模型。在千秒差距尺度下，射束速度是相对论性的（Γ ε 4），支持了几个河外喷流的X射线发射可能是由于相对论性增强的CMB光子的想法。所有模型的射电辐射主要由热点贡献决定。所有的模型都表现出凹陷的腔内部的X射线表面亮度，与最近的观测结果一致。
We study the influence of the matter content of extragalactic jets on their morphology, dynamics and emission properties. For this purpose we consider jets of extremely different compositions, including pure leptonic and baryonic plasmas. Our work is based on two-dimensional relativistic hydrodynamic simulations of the long-term evolution of powerful extragalactic jets propagating into a homogeneous environment. The equation of state used in the simulations accounts for an arbitrary mixture of electrons, protons and electron–positron pairs. Using the hydrodynamic models, we have also computed synthetic radio maps and the thermal bremsstrahlung X-ray emission from their cavities.
Although there is a difference of about three orders of magnitude in the temperatures of the cavities inflated by the simulated jets, we find that both the morphology and the dynamic behaviour are almost independent of the assumed composition of the jets. Their evolution proceeds in two distinct epochs. During the first one, multidimensional effects are unimportant and the jets propagate ballistically. The second epoch starts when the first larger vortices are produced near the jet head, causing the beam cross-section to increase and the jet to decelerate. The evolution of the cocoon and cavity is in agreement with a simple theoretical model. The beam velocities are relativistic (Γ≃4) at kiloparsec scales, supporting the idea that the X-ray emission of several extragalactic jets may be due to relativistically boosted CMB photons. The radio emission of all models is dominated by the contribution of the hotspots. All models exhibit a depression in the X-rays surface brightness of the cavity interior, in agreement with recent observations.
东安格利亚大学/布里斯托大学（英国）
DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
通讯作者：
--