文章基本信息

标题：First 3 mm-VLBI imaging of the two-sided jet in Cygnus A - Zooming into the launching region
其他标题：Zooming into the launching region
本地全文：下载
作者：B. Boccardi ; B. Boccardi ; T. P. Krichbaum 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2016
卷号：588
页码：1-4
DOI：10.1051/0004-6361/201628412
语种：English
出版社：EDP Sciences
摘要：Aims. We present for the first time Very Long Baseline Interferometry images of the radio galaxy Cygnus A at the frequency of 86 GHz. Thanks to the high spatial resolution of only ~200 Schwarzschild radii (RS), such observations provide an extremely detailed view of the nuclear regions in this archetypal object and allow us to derive important constraints for theoretical models describing the launching of relativistic jets. Methods. A pixel-based analysis of the jet outflow, which still appears two-sided on the scales probed, was performed. By fitting Gaussian functions to the transverse intensity profiles, we could determine the jet width in the nuclear region. Results. The base of the jets appears wide. The minimum measured transverse width of ~(227 ± 98) RS is significantly larger than the radius of the innermost stable circular orbit, suggesting that the outer accretion disk is contributing to the jet launching. The existence of a faster and Doppler de-boosted inner section, powered either from the rotation of the inner regions of the accretion disk or by the spinning black hole, is suggested by the kinematic properties and by the observed limb brightening of the flow.
关键词：instrumentation: high angular resolution;galaxies: active;galaxies: jets