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首页> 外文期刊>The Astrophysical journal >JET DIRECTIONS IN SEYFERT GALAXIES
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JET DIRECTIONS IN SEYFERT GALAXIES

机译：塞弗特星系中的喷气方向

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Here we present the study of the relative angle between the accretion disk (or radio jet) and the galaxy disk for a sample of Seyfert galaxies selected from a mostly isotropic property, the 60 μm flux, and warm infrared colors. We used VLA A-array 3.6 cm continuum data and ground-based optical imaging, homo- geneously observed and reduced to minimize selection effects. For parts of the analysis we enlarged the sample by including galaxies serendipitously selected from the literature. For each galaxy we have a pair of points (i,δ), which are the inclination of the galaxy relative to the line of sight and the angle between the jet projected into the plane of the sky and the host galaxy major axis, respectively. For some galaxies we also had information about which side of the minor axis is closer to Earth. This data is combined with a statistical technique, developed by us, to determine the distribution of β angles in three dimen- sions, the angle between the jet and the host galaxy plane axis. We found from an initial analysis of the data of the 60 μm sample, where Seyfert 1 and 2 galaxies were not differentiated, that the observed distribution of i and δ values can be well represented either by a homogeneous sin β distribution in the range 0° ≤ β ≤ 90° or in 0° ≤ β ≤ 65°, but not by an equatorial ring. A more general model, which tested β-distributions in the range β_1 ≤ β ≤ β_2, for different ranges of β_1 and β_2 values, required β_2 to be larger than 65° and gave preference for β_1 smaller than 40°-　50°. An important result from our analysis was obtained when we determined whether the jet was projected against the near or the far side of the galaxy and differentiated between Seyfert 1 and Seyfert 2 galaxies, which showed that the model could not represent Seyfert 1 galaxies adequately. We found that the inclusion of viewing angle restrictions for Seyfert 1 galaxies, namely, that a galaxy can be recognized as a Seyfert 1 only if the angle between the jet and the line of sight (| Φ | ) is smaller than a given angle Φ_c and that the galaxy inclina- tion i is smaller than an angle I_c, gave rise to statistically acceptable models. This indication that there is a difference in viewing angle to the central engine between Seyfert 1 galaxies and Seyfert 2 galaxies is a direct and independent confirmation of the underlying concepts of the unified model. We discuss possible explanations for the misalignment between the accretion disk and the host galaxy disk : warping of the accretion disk by self irradiation instability, by the Bardeen-Petterson effect, or by a misaligned gravita- tional potential of a nuclear star cluster surrounding the black hole, as well as feeding of the accretion disk by a misaligned inflow of gas from minor mergers, capture of individual stars or gas from the nuclear star cluster, and the capture of individual molecular clouds from the host galaxy.
机译：在这里，我们对塞弗特星系样本的吸积盘（或射电射流）与星系盘之间的相对角度进行研究，这些样本选自各向同性，60μm通量和暖红外色。我们使用VLA A阵列3.6厘米连续数据和基于地面的光学成像，进行了均匀观察和缩小，以最大程度地减少选择效果。对于部分分析，我们通过包括从文献中偶然选出的星系来扩大样本。对于每个星系，我们都有一对点（i，δ），分别是星系相对于视线的倾斜度和投射到天空平面的射流与主星系主轴之间的夹角。对于某些星系，我们还获得了有关短轴哪一侧更靠近地球的信息。该数据与我们开发的统计技术相结合，可以确定三个角度（射流与主星系平面轴之间的角度）的β角分布。我们从对60μm样本数据的初步分析中发现，没有区分Seyfert 1星系和2星系，观察到的i和δ值分布可以很好地表示为0°范围内的均匀sinβ分布。 ≤β≤90°或在0°≤β≤65°中，但不通过赤道环。对于β_1和β_2值的不同范围，测试在β_1≤β≤β_2范围内的β分布的更通用的模型要求β_2大于65°，并且优先选择β_1小于40°-β50°。当我们确定射流是投射在银河系的近侧还是远侧并区分塞弗特1星系和塞弗特2星系时，从我们的分析中获得了重要的结果，这表明该模型不能充分代表塞弗特1星系。我们发现包含塞弗特1星系的视角限制，即只有当射流与视线之间的角度（|Φ|）小于给定角度Φ_c时，星系才能被识别为塞弗特1。并且银河系的倾斜角i小于角度I_c，从而产生了统计学上可接受的模型。这表明塞弗特1星系和塞弗特2星系在中央引擎的视角上存在差异，这是对统一模型基本概念的直接和独立确认。我们讨论了吸积盘与主星系盘之间未对准的可能解释：由于自身辐射不稳定性，巴丁-佩特森效应或围绕黑色的核星团的引力失准而引起的吸积盘翘曲孔，以及由于小合并产生的未对准的气体流入，从核星团中捕获单个恒星或气体，以及从宿主星系中捕获单个分子云，从而为积聚盘提供了动力。

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