Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
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DOI：
10.1093/pasj/psx054
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发表时间：
2017-06
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通讯作者：
K. Hada;Jong Ho Park;M. Kino;K. Niinuma;B. Sohn;H. Ro;T. Jung;J. Algaba;Guangyao Zhao;Sang-Sung Lee;K. Akiyama;S. Trippe;K. Wajima;S. Sawada-Satoh;F. Tazaki;I. Cho;J. Hodgson;J. Lee;Y. Hagiwara;M. Honma;S. Koyama;Junghwan Oh;Taeseak Lee;H. Yoo;N. Kawaguchi;D. Roh;Se-jin Oh;J. Yeom;Dong-Kyu Jung;C. Oh;H. Kim;Ju-Yeon Hwang;D. Byun;Se-Hyung Cho;Hyun-Goo Kim;H. Kobayashi;K. Shibata
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作者：
K. Hada;Jong Ho Park;M. Kino;K. Niinuma;B. Sohn;H. Ro;T. Jung;J. Algaba;Guangyao Zhao;Sang-Sung Lee;K. Akiyama;S. Trippe;K. Wajima;S. Sawada-Satoh;F. Tazaki;I. Cho;J. Hodgson;J. Lee;Y. Hagiwara;M. Honma;S. Koyama;Junghwan Oh;Taeseak Lee;H. Yoo;N. Kawaguchi;D. Roh;Se-jin Oh;J. Yeom;Dong-Kyu Jung;C. Oh;H. Kim;Ju-Yeon Hwang;D. Byun;Se-Hyung Cho;Hyun-Goo Kim;H. Kobayashi;K. Shibata
我们报告了由KVN和Vera阵列(KAVA)在22 GHz获得的关于活动星系M87射电喷流的高节奏监测计划的初步结果。这是一项先于更大规模的Kava-M87监测计划的试点研究，目前正在进行中。从2013年12月至2014年6月，试点监测大多每隔两到三周进行一次，记录速率为1Gbps，共获得10个纪元的数据。我们成功地获得了一系列高质量的射电图，揭示了这一喷流在~lt；~1-20 Ma的丰富结构，对应于~0.1-2pC(或~140-2800 Schwarzschild半径)的物理尺度(投影)。我们在这些尺度上探测到了超光速运动，并有逐渐加速的趋势。最近在43 GHz的VLBA研究中获得了喷流底部附近如此快速运动和加速的第一个证据，而不同仪器在不同频率和时间看到非常相似的运动学这一事实表明，这些特性是这种喷流的基本特征。这项试验计划表明，KAVA是一个强大的VLBI阵列，用于研究M87喷流和其他相对论喷流的详细结构演变。
We report the initial results of our high-cadence monitoring program on the radio jet in the active galaxy M87, obtained by the KVN and VERA Array (KaVA) at 22 GHz. This is a pilot study that preceded a larger KaVA-M87 monitoring program, which is currently ongoing. The pilot monitoring was mostly performed every two to three weeks from December 2013 to June 2014, at a recording rate of 1 Gbps, obtaining the data for a total of 10 epochs. We successfully obtained a sequence of good quality radio maps that revealed the rich structure of this jet from <~1 mas to 20 mas, corresponding to physical scales (projected) of ~0.1-2 pc (or ~140-2800 Schwarzschild radii). We detected superluminal motions at these scales, together with a trend of gradual acceleration. The first evidence for such fast motions and acceleration near the jet base were obtained from recent VLBA studies at 43 GHz, and the fact that very similar kinematics are seen at a different frequency and time with a different instrument suggests these properties are fundamental characteristics of this jet. This pilot program demonstrates that KaVA is a powerful VLBI array for studying the detailed structural evolution of the M87 jet and also other relativistic jets.