The kinematic of HST-1 in the jet of M 87
The kinematic of HST-1 in the jet of M 87
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DOI：
10.1051/0004-6361/201218794
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发表时间：
2012-01
影响因子：
6.5
通讯作者：
K. Hada;M. Giroletti;G. Giovannini;C. Casadio;M. Beilicke;A. Cesarini;Teddy Cheung;Akihiro Doi;Henric;Krawczynski;M. Kino;Nick Lee;H. Nagai
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文献类型：
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作者：
K. Hada;M. Giroletti;G. Giovannini;C. Casadio;M. Beilicke;A. Cesarini;Teddy Cheung;Akihiro Doi;Henric;Krawczynski;M. Kino;Nick Lee;H. Nagai
目的。我们旨在确定M87射电喷流下游HST - 1区域内的结构变化，包括一般情况以及与极高能（VHE）活动事件的关联。方法。我们分析并比较了2006年至2011年间对M87喷流进行的26次甚长基线干涉测量（VLBI）观测结果，这些观测是利用1.7吉赫兹的甚长基线阵列（VLBA）和5吉赫兹的欧洲甚长基线干涉测量网（EVN）进行的。结果。在所有观测时刻都探测到了HST - 1；我们用两个或更多个分量对其复杂结构进行了模型拟合，其中最外侧的两个分量显示出显著的自行，其超光速约为4c左右。在上游探测到的第三个特征的运动更难以描述。在我们观测期间，HST - 1的整体位置角从 - 65°变为 - 90°，同时该结构向下游移动了超过80毫角秒。我们关于分量演化的结果表明，HST - 1上游边缘的结构变化可能与VHE事件有关。
Aims. We aim to constrain the structural variations within the HST-1 region downstream of the radio jet of M87, in general as well as in connection to the episodes of activity at very high energy (VHE). Methods. We analyzed and compared 26 VLBI observations of the M87 jet, obtained between 2006 and 2011 with the Very Long Baseline Array (VLBA) at 1.7 GHz and the European VLBI Network (EVN) at 5 GHz. Results. HST-1 is detected at all epochs; we model-fitted its complex structure with two or more components, the two outermost of which display a significant proper motion with a superluminal velocity around ∼4c. The motion of a third feature that is detected upstream is more difficult to characterize. The overall position angle of HST-1 has changed during the time of our observations from −65 ◦ to −90 ◦ , while the structure has moved by over 80 mas downstream. Our results on the component evolution suggest that structural changes at the upstream edge of HST-1 can be related to the VHE events.