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arXiv 1111.1196astro-ph.GA
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从DG Tau喷流中的节点的无线电连续辐射

Radio continuum emission from knots in the DG Tau jet

L. F. Rodriguez, R. F. Gonzalez, A. C. Raga, J. Canto, A. Riera, L. Loinard, S. A. Dzib, L. A. Zapata

摘要:

内容:HH 158是来自年轻恒星DG Tau的喷流,是少数几个在光学和X射线波长下检测到喷流结的来源之一。目的:利用甚大天线阵对该源的观测,搜索无线电节点,如果发现,将其与光学和X射线节点进行比较。模拟无线电节点的辐射。研究方法:我们分析了存档数据,并获得了这个源的新的甚大阵列观测,以及光学图像,以测量结的当前位置。我们还模拟了无线电发射的纽结在冲击射流与内在的时间依赖性喷射速度。结果:我们检测到无线电节点在1996.98和2009.62 VLA数据。在误差范围内,这些无线电节点与光学节点重合。我们也令人满意地模拟了观测到的无线电通量密度从喷流与内在的变化冲击功能。所有观测到的无线电、光学和X射线结的位置都可以解释为四个连续的结,以4.80年的周期喷出,并以198 km/s $^{-1}$的速度在天空平面上离开源。结论:射电和光学结在空间上是相关的,我们的模型可以解释观测到的射电通量密度。然而,X射线结似乎没有光学或无线电对应物,其性质仍然知之甚少。

英文摘要:

Context: HH 158, the jet from the young star DG Tau, is one of the few sources of its type where jet knots have been detected at optical and X-ray wavelengths. Aims: To search, using Very Large Array observations of this source, radio knots and if detected, compare them with the optical and X-ray knots. To model the emission from the radio knots. Methods: We analyzed archive data and also obtained new Very Large Array observations of this source, as well as an optical image, to measure the present position of the knots. We also modeled the radio emission from the knots in terms of shocks in a jet with intrinsically time-dependent ejection velocities. Results: We detected radio knots in the 1996.98 and 2009.62 VLA data. These radio knots are,within error, coincident with optical knots. We also modeled satisfactorily the observed radio flux densities as shock features from a jet with intrinsic variability. All the observed radio, optical, and X-ray knot positions can be intepreted as four successive knots, ejected with a period of 4.80 years and traveling away from the source with a velocity of 198 km s$^{-1}$ in the plane of the sky. Conclusions: The radio and optical knots are spatially correlated and our model can explain the observed radio flux densities. However, the X-ray knots do not appear to have optical or radio counterparts and their nature remains poorly understood.

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