The dense plasma torus around the nucleus of an active galaxy ngc 1052
The dense plasma torus around the nucleus of an active galaxy ngc 1052
复制标题
活跃星系 ngc 1052 核心周围的致密等离子体环
DOI：
--
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
K. Wajima
中科院分区：
文献类型：
--
作者：
S. Kameno;S. Sawada;M. Inoue;Z. Shen;K. Wajima
一个围绕活动星系核的亚秒差距尺度的致密等离子体环被揭开。我们报告甚长基线干涉（VLBI）观测在2.3，8.4和15.4 GHz的活动星系NGC 1052。双面喷流和原子核的凸光谱表明，同步辐射被前景冷等离子体通过自由-自由吸收（FFA）遮蔽。产生三色图像以说明FFA不透明度的分布。我们发现了一个中心凝聚的等离子体覆盖约0.1 PC和0.7 PC的接近和后退的射流，分别。对这种不对称分布的一个简单解释是垂直于喷流的厚等离子体环的存在。我们还发现了一个环境FFA吸收，其密度分布可以归因于等温国王模型的球形分布。等离子体的环面和球形分布的共存表明从径向吸积到旋转吸积的过渡。
A subparsec-scale dense plasma torus around an active galactic nucleus is unveiled. We report on very-longbaseline interferometry (VLBI) observations at 2.3, 8.4, and 15.4 GHz towards the active galaxy NGC1052. The convex spectra of the double-sided jets and the nucleus imply that synchrotron emission is obscured through free– free absorption (FFA) by the foreground cold dense plasma. A trichromatic image was produced to illustrate the distribution of the FFA opacity. We found a central condensation of the plasma which covers about 0.1 pc and 0.7 pc of the approaching and receding jets, respectively. A simple explanation for the asymmetric distribution is the existence of a thick plasma torus perpendicular to the jets. We also found an ambient FFA absorber, whose density profile can be ascribed to a spherical distribution of the isothermal King model. The coexistence of torus-like and spherical distributions of the plasma suggests a transition from radial accretion to rotational accretion around the nucleus.