论文标题
重新访问旧（AGN）朋友 - 光谱外观发生了变化
Revisiting old (AGN) friends -- what's changed in their spectral looks
论文作者
论文摘要
长期以来，活跃的银河核（AGN）是可变的，但是这些变化的幅度，时间尺度和性质通常会因物体到对象而异。有关AGN和驱动这些驱动的物理过程的最丰富的信息来源仍然是光谱。尽管对于某些AGN数十年来，这种频谱一直保持着非常稳定的稳定，但其他被称为变化AGN的物体经历了全面的光谱转换。检测技术中的发展已在其他波段中详细探测，例如，高能发射通常会大不相同。本文探讨了一些已知（几乎被遗忘的）塞弗特星系的当前特征。它比较了他们目前的光谱特性，该特性取决于南非天文天文台的最新观察结果，并比较了早期的时期。此外，它还考虑了发生的变化的含义，替代特定光谱特征的耐力，对我们对观察到的靶标的机制，尤其是对AGN模型的理解。
Active Galactic Nuclei (AGN) have long been known to be variable, but the amplitude, timescale and nature of these changes can often differ dramatically from object to object. The richest source of information about the properties of AGN and the physical processes driving these remains the optical spectrum. While this spectrum has remained remarkably steady over decades for some AGN, other objects, referred to as Changing Look AGN, have experienced a comprehensive spectral transformation. Developments in the detection technology have enabled detailed probing in other wavebands, highlighting for example often quite different variability patterns for high energy emission. This paper explores the current characteristics of some long-known (and almost forgotten) Seyfert galaxies. It compares their present optical spectral properties, determined from recent observations at the South African Astronomical Observatory, with those from much earlier epochs. It furthermore considers the implication of the changes that have taken place, alternatively the endurance of specific spectral features, on our understanding of the mechanisms of the observed targets in particular, and on AGN models in general.
