旋进喷流系统SS433 III的结构和磁场。来自深多时期VLA活动的喷流的固有亮度的演变
Structure and Magnetic Fields in the Precessing Jet System SS433 III. Evolution of the Intrinsic Brightness of the Jets from a Deep Multi-Epoch VLA Campaign
摘要：
我们提出了一个序列的SS 433在2007年夏天使用的VLA在A配置在5和8 GHz的五个深观测。在本文中，我们研究了喷流的亮度轮廓及其时间演化。我们还研究了源中的光谱指数分布。我们发现（如先前报告的一个单一的早期图像的分析），如果投影和多普勒波束的东部和西部射流的配置文件是非常相似的。这五幅图像的序列使我们能够从源自核心的喷流功率的变化中解开单个喷流的亮度演变。我们发现，每片喷流的亮度衰减作为年龄（或距离核心）的指数函数，exp（-τ/τ '），其中τ是发射时的年龄和τ' = 55.9 +-1.7天。这个演化模型同样很好地描述了东、西急流。也有显着的变化（至少5倍），在喷流功率与出生时代，与东部和西部射流同步变化。在光学巴耳末线辐射（10^15 cm）和射电辐射（10^17 cm）的尺度之间没有减速，这就要求喷流物质比周围的物质密度大得多。我们发现密度比必须超过300：1。
英文摘要：
We present a sequence of five deep observations of SS433 made over the summer of 2007 using the VLA in the A configuration at 5 and 8 GHz. In this paper we study the brightness profiles of the jets and their time evolution. We also examine the spectral index distribution in the source. We find (as previously reported from the analysis of a single earlier image) that the profiles of the east and west jets are remarkably similar if projection and Doppler beaming are taken into account. The sequence of five images allows us to disentangle the evolution of brightness of individual pieces of jet from the variations of jet power originating at the core. We find that the brightness of each piece of the jet fades as an exponential function of age (or distance from the core), exp(-tau/tau'), where tau is the age at emission and tau' = 55.9 +- 1.7 days. This evolutionary model describes both the east and west jets equally well. There is also significant variation (by a factor of at least five) in jet power with birth epoch, with the east and west jets varying in synchrony. The lack of deceleration between the scale of the optical Balmer line emission (10^15 cm) and that of the radio emission (10^17 cm) requires that the jet material is much denser than its surroundings. We find that the density ratio must exceed 300:1.
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