A transition from parabolic to conical shape as a common effect in nearby AGN jets
A transition from parabolic to conical shape as a common effect in nearby AGN jets
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从抛物线形状到圆锥形状的转变是附近 AGN 喷流的常见效应
DOI：
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
T. Savolainen
中科院分区：
文献类型：
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作者：
Y. Kovalev;A. Pushkarev;E. Nokhrina;A. Plavin;V. Beskin;A. Chernoglazov;M. Lister;T. Savolainen
对活动星系核(AGN)中喷流准直现象的观测研究是了解其形成和加速过程的关键。我们已经使用15 GHz和1.4 GHz的VLBA数据对367个AGN样本中的喷流形状转变进行了自动搜索。这次搜索发现了红移z<；0.07处的29个附近喷流中的10个，它们从抛物线形状转变为圆锥形，而完整分析的样品以较远的活动星系核为主，典型的z约为1。这10个活动星系核是UGC00773、NGC1052、3C111、3C120、TXS0815-094、MRK180、PKS1514+00、NGC6251、3C371和BLLac。我们得出结论，几何转变可能是活动星系核喷流中的一种常见效应。只有当获得足够的线性分辨率时，才能观察到它。补充这些结果与之前报道的附近AGN 1H0323+342和M87的形状断裂相补充，我们估计断裂发生在距离原子核10^5-10^6引力半径处。我们认为，当体等离子体动能通量等于Pointing能通量时，喷流形状发生转变，而环境介质压力由Bondi吸积控制。通常，断点可能与邦迪半径不重合。观测数据支持我们对喷流加速和断点性质的模型预测。
Observational studies of collimation in jets in active galactic nuclei (AGN) are a key to understanding their formation and acceleration processes. We have performed an automated search for jet shape transitions in a sample of 367 AGN using VLBA data at 15 GHz and 1.4 GHz. This search has found ten out of 29 nearby jets at redshifts z<0.07 with a transition from a parabolic to conical shape, while the full analyzed sample is dominated by distant AGN with a typical z about 1. The ten AGN are UGC00773, NGC1052, 3C111, 3C120, TXS0815-094, Mrk180, PKS1514+00, NGC6251, 3C371, and BL Lac. We conclude that the geometry transition may be a common effect in AGN jets. It can be observed only when sufficient linear resolution is obtained. Supplementing these results with previously reported shape breaks in the nearby AGN 1H0323+342 and M87, we estimate that the break occurs at 10^5-10^6 gravitational radii from the nucleus. We suggest that the jet shape transition happens when the bulk plasma kinetic energy flux becomes equal to the Poynting energy flux, while the ambient medium pressure is assumed to be governed by Bondi accretion. In general, the break point may not coincide with the Bondi radius. The observational data supports our model predictions on the jet acceleration and properties of the break point.
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影响因子：
6.5
作者：
T. Hovatta;S. O’Sullivan;I. Martí-Vidal;T. Savolainen;A. Tchekhovskoy;A. Tchekhovskoy
通讯作者：
T. Hovatta;S. O’Sullivan;I. Martí-Vidal;T. Savolainen;A. Tchekhovskoy;A. Tchekhovskoy
影响因子：
4.8
作者：
K. Chatterjee;M. Liska;A. Tchekhovskoy;S. Markoff
通讯作者：
K. Chatterjee;M. Liska;A. Tchekhovskoy;S. Markoff
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.
影响因子：
6.5
作者：
C. Müller;M. Kadler;R. Ojha;R. Ojha;R. Ojha;M. Perucho;C. Grossberger;E. Ros;E. Ros;J. Wilms;J. Blanchard;M. Böck;B. Carpenter;M. Dutka;P. G. Edwards;H. Hase;S. Horiuchi;A. Kreikenbohm;J. Lovell;A. Markowitz;A. Markowitz;C. Phillips;C. Plötz;T. Pursimo;J. Quick;R. Rothschild;R. Schulz;T. Steinbring;J. Stevens;J. Trüstedt;A. Tzioumis
通讯作者：
C. Müller;M. Kadler;R. Ojha;R. Ojha;R. Ojha;M. Perucho;C. Grossberger;E. Ros;E. Ros;J. Wilms;J. Blanchard;M. Böck;B. Carpenter;M. Dutka;P. G. Edwards;H. Hase;S. Horiuchi;A. Kreikenbohm;J. Lovell;A. Markowitz;A. Markowitz;C. Phillips;C. Plötz;T. Pursimo;J. Quick;R. Rothschild;R. Schulz;T. Steinbring;J. Stevens;J. Trüstedt;A. Tzioumis