A Systematic Survey for z < 0.04 Changing-Look AGNs
Madhooshi R. Senarath, Michael J. I. Brown, Michelle E. Cluver, Thomas H. Jarrett, Christian Wolf, Nicholas P. Ross, John R. Lucey, Vaishali Parkash, Wei J. Hon
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Accepted for publication in the Monthly Notices of the Royal Astronomical Society; 15 pages, 9 figures and 4 tables
We have conducted a systematic survey for z $<$ 0.04 active Galactic nuclei (AGNs) that may have changed spectral class over the past decade. We use SkyMapper, Pan-STARRS and the Véron-Cetty & Véron (2010) catalogue to search the entire sky for these ``changing-look'' AGNs using a variety of selection methods, where Pan-STARRS has a coverage of 3$π$ steradians (sky north of Declination $-30^\circ$) and SkyMapper has coverage of $\sim$ 21,000$~\rm{deg^2}$ (sky south of Declination $0^\circ$). We use small aperture photometry to measure how colour and flux have changed over time, where a change may indicate a change in spectral type. Optical colour and flux are used as a proxy for changing H$α$ equivalent width, while WISE 3.4 $μ$m flux is used to look for changes in the hot dust component. We have identified four AGNs with varying spectra selected using our optical colour selection method. Three AGNs were confirmed from recent observations with WiFeS on the 2.3 m telescope at Siding Spring and the other was identified from archival spectra alone. From this, we identify two new changing look AGNs; NGC 1346 and 2MASX J20075129-1108346. We also recover Mrk 915 and Mrk 609, which are known to have varying spectra in the literature, but they do not meet our specific criteria for changing look AGNs.
Discovery of Repeating Transitions in 16 Changing-look Active Galactic Nuclei
Xiamen University（厦门大学）；Quanzhou Normal University（泉州师范学院）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；University of Science and Technology of China（中国科学技术大学）；Yunnan Normal University（云南师范大学）
Radio Activity Across Accretion State Changes in Changing-look AGNs: Insights from FIRST and VLASS over Two Decades
School of Physics and Technology, Nanjing Normal University（南京师范大学物理科学与技术学院）；Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台光学天文重点实验室）；European Southern Observatory（欧洲南方天文台）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（教育部现代天文与天体物理学重点实验室（南京大学））
Searching for changing-state AGNs in massive datasets -- I: applying deep learning and anomaly detection techniques to find AGNs with anomalous variability behaviours
活动星系核（AGN）的经典分类方案最近受到了所谓的变态（变貌）AGN（CSAGNs）的发现的挑战。这一现象背后的物理机制仍然是一个公开辩论的问题，样本太小，而且是偶然发现的，无法提供可靠的答案。为了解决这个问题，我们需要设计能够在改变状态的行为中检测AGN的方法。在这里，我们提出了一个异常检测（AD）技术，旨在识别活动星系核的光变曲线与异常行为在大量的数据集。这项技术的主要目的是在转变的不同阶段识别CSAGN，但它也可以用于更一般的目的，例如清理AGN可变性分析的大规模数据集。我们使用的光变曲线来自Zwicky Transient Facility数据发布5（ZTF DR 5），包含230，451个不同类别的AGN样本。ZTF DR 5光变曲线采用变分递归自动编码器（VRAE）架构建模，这使我们能够从VRAE潜在空间中获得一组属性，这些属性描述了我们样本的一般行为。然后，这些属性被用作隔离森林（IF）算法的特征，该算法是针对“一类”问题的异常检测器。我们使用VRAE重建误差和IF异常评分来选择8，809个异常的样本。这些异常主要是由虚假的候选人，但我们能够确定75个有希望的CSAGN候选人。
Changing-Look Active Galactic Nuclei in SDSS-V: Host-Galaxy Properties and Black-Hole Scaling Relations
Tel Aviv University（特拉维夫大学）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理研究所）；Excellence Cluster ORIGINS（ORIGINS卓越集群）；The Pennsylvania State University（宾夕法尼亚州立大学）；University of Washington（华盛顿大学）；University of Geneva（日内瓦大学）；Universidad Diego Portales（迭戈·波特莱斯大学）；Peking University（北京大学）
The physical mechanism for two rapid changing-look AGNs: SDSS J0225+0030 and SDSS J1723+5504
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；Institute for Astronomy, School of Physics, Zhejiang University（浙江大学物理学院天体物理研究所）；Department of Astronomy, Xiamen University（厦门大学天文学系）
Are "Changing-Look" Active Galactic Nuclei Special in the Coevolution of Supermassive Black Holes and their Hosts? II. The Case of Changing-Look Narrow-Line Seyfert 1 Galaxies
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University（广西大学物理科学与技术学院相对论天体物理广西重点实验室）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；Department of Astronomy, University of California, Berkeley（加州大学伯克利分校天文学系）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）
Peking University（北京大学）；Heidelberg University（海德堡大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
Polarization properties of changing-look active galactic nuclei: NGC 1365 and NGC 2992
Foundation for Research and Technology-Hellas (FORTH)（希腊研究与技术基金会）；Instituto de Astrofisica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；National Astronomical Observatory of Japan（日本国立天文台）
22 Newly Identified Repeating Changing-look AGNs and Evidence for Extreme Broad-line Region Breathing
Aryabhatta Research Institute of Observational Sciences (ARIES)（阿亚巴塔观测科学研究所）；Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences（中国科学院天体结构与演化重点实验室）
Monitoring AGNs with Hβ Asymmetry. II. Reverberation Mapping of Three Seyfert Galaxies Historically Displaying Hβ Profiles with Changing Asymmetry: Mrk 79, NGC 3227, and Mrk 841
OQ~208: A New Fe~II Changing-look Active Galactic Nucleus and Implications for the Nature of the Changing-look Phenomenon
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Department of Astronomy, University of California, Berkeley（加州大学伯克利分校天文学系）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University（广西大学物理科学与技术学院相对论天体物理重点实验室）
Morphology of Optical Changing-Look AGN-host Galaxies: Evidence for an Important Role of Mergers
Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；University of Chinese Academy of Sciences（中国科学院大学）；State Key Laboratory of Radio Astronomy and Technology, Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台射电天文与技术重点实验室）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）
Systematic Study of AGN Clumpy Tori with Broadband X-ray Spectroscopy: Updated Unified Picture of AGN Structure
我们提出了使用X射线cluttertorus模型对附近活动星系核（AGN）进行系统的宽带X射线光谱分析的结果（XCLUMPY; Tanimoto et al. 2019）。通过增加本文新分析的16个活动星系核，我们研究了Ichikawa et al.（2015）和García-Bernete et al.（2019）的28个活动星系核，包括未吸收和吸收的活动星系核。这是最大的样品，其X射线和红外光谱分别由cluplantorus模型XCLUMPY和CLUMPY（Nenkova等人，2008）进行分析。根据每个物体的X射线环面参数确定的爱丁顿比和环面覆盖因子之间的关系遵循Ricci等人（2017）基于统计分析发现的趋势。我们证实了Tanimoto等人（2020）的结果：（1）红外数据确定的环面角宽度大于X射线数据确定的环面角宽度;（2）在遮蔽活动星系核中，沿视线方向的氢柱密度与V波段消光比（$N_{\rm H}/A_{\rm V}$）与银河系的平均值相似。未遮蔽的活动星系核的视向$N_{\rm H}/A_{\rm V}$比明显小于银河系的视向比。我们的研究结果可以很好地解释了一个更新的统一的图片AGN结构，包括一个尘埃环，尘埃极地流出，和无尘气体，其中的倾斜度决定了X射线和光学分类和观测到的环面属性在X射线和红外波段。
The Hunt for Red Dual AGNs I: Spatially-Resolved Mid-IR Dual AGNs in the DESI Legacy Imaging Surveys
U.S. Naval Observatory（美国海军天文台）；CRESST II, CSST, University of Maryland Baltimore County（马里兰大学巴尔的摩县分校）；Oak Ridge Associated Universities（橡树岭联合大学）；X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center（NASA戈达德太空飞行中心X射线天体物理实验室）；Department of Physics and Astronomy, George Mason University（乔治梅森大学物理与天文学系）；Southeastern Universities Research Association（东南大学研究协会）；Center for Research and Exploration in Space Science and Technology, NASA/GSFC（NASA/戈达德太空飞行中心空间科学与技术研究探索中心）；U.S. Naval Research Laboratory（美国海军研究实验室）
