A flare in the optical spotted in the changing-look Seyfert NGC 3516
D. Ilic, V. Oknyansky, L. C. Popovic, S. S. Tsygankov, A. A. Belinski, A. M. Tatarnikov, A. V. Dodin, N. I. Shatsky, N. P. Ikonnikova, N. Rakic, A. Kovacevic, S… 展开作者
D. Ilic, V. Oknyansky, L. C. Popovic, S. S. Tsygankov, A. A. Belinski, A. M. Tatarnikov, A. V. Dodin, N. I. Shatsky, N. P. Ikonnikova, N. Rakic, A. Kovacevic, S. Marceta-Mandic, M. A. Burlak, E. O. Mishin, N. V. Metlova, S. A. Potanin, S. G. Zheltoukhov
备注：
7 pages, 6 figures, accepted in A&A (corrected after receiving comments from the language editor)
我们介绍了从2019年9月到2020年1月的短期密集光学活动中观察到的变化外观的Seyfert NGC 3516。这个活动星系核被认为具有很强的光学可变性，并且在过去改变了它的类型。自2013年以来，它一直处于光学的低活动状态，从2015年底到2016年初，它一直处于休眠状态。我们的目标是从U-和B-波段的新观测中研究NGC 3516的光度和光谱变化，并检查光学宽发射线的轮廓，以证明该物体可能正在进入一个新的活动状态。NGC 3516在过去的4个月里一直受到U和B过滤器的自动望远镜的密切监测，能够实现0.01精度的精确测光。光谱观测是在发现亮度增加时触发的。我们支持我们的分析与紫外线和X射线的长期光变曲线从档案斯威夫特数据构建的暴力变化的过去情节。在U和B滤波器中可以看到光度星等的增加，最大幅度分别为0.25等和0.1等。在耀斑期间，我们观察到比以前报道的更强的禁戒高电离铁线，以及复杂的宽Ha和Hb线。这一点在Ha中尤其明显，它似乎是双峰。看来巴耳末线中出现了一个宽度约为10，000 km/s的非常宽的分量。光学、紫外和X射线光变曲线的趋势是相似的，在紫外和X射线波段的情况下，变化幅度明显更大。连续辐射的增加、冕线的变化以及巴耳末线中非常宽的分量可能表明NGC 3516活动星系核终于离开了它过去3年来一直处于的低活动状态。
英文摘要：
We present observations from the short-term intensive optical campaign (from Sep2019 to Jan2020) of the changing-look Seyfert NGC 3516. This active galactic nucleus is known to have strong optical variability and has changed its type in the past. It has been in the low-activity state in the optical since 2013, with some rebrightening from the end of 2015 to the beginning of 2016, after which it remained dormant. We aim to study the photometric and spectral variability of NGC 3516 from the new observations in U- and B-bands and examine the profiles of the optical broad emission lines in order to demonstrate that this object may be entering a new state of activity. NGC 3516 has been monitored intensively for the past 4 months with an automated telescope in U and B filters, enabling accurate photometry of 0.01 precision. Spectral observations were triggered when an increase in brightness was spotted. We support our analysis of past-episodes of violent variability with the UV and X-ray long-term light curves constructed from the archival Swift data. An increase of the photometric magnitude is seen in both U and B filters to a maximum amplitude of 0.25mag and 0.1 mag, respectively. During the flare, we observe stronger forbidden high-ionization iron lines than reported before, as well as the complex broad Ha and Hb lines. This is especially seen in Ha which appears to be double-peaked. It seems that a very broad component of ~10,000 km/s in width in the Balmer lines is appearing. The trends in the optical, UV, and X-ray light curves are similar, with the amplitudes of variability being significantly larger in the case of UV and X-ray bands. The increase of the continuum emission, the variability of the coronal lines, and the very broad component in the Balmer lines may indicate that the AGN of NGC 3516 is finally leaving the low-activity state in which it has been for the last ~3 years.
Searching for similarities in the accretion flow of Seyfert 1 galaxies and cataclysmic variables based on flare profiles of IRAS 13224-3809, 1H 0707-495, Mrk 766 and MV Lyr
Identifying Changing-Look AGN Transitions in Light Curve Data with the Zwicky Transient Facility
University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；National Center for Supercomputing Applications（国家超级计算应用中心）；Washington State University（华盛顿州立大学）；Yale University（耶鲁大学）；The Pennsylvania State University（宾夕法尼亚州立大学）
Back from the dead: AT2019aalc as a candidate repeating TDE in an AGN
Ruhr Astroparticle and Plasma Physics Center (RAPP Center)（鲁尔天体物理与等离子体物理中心）；Leiden Observatory, Leiden University（莱顿天文台，莱顿大学）；Deutsches Elektronen-Synchrotron (DESY)（德国电子同步辐射中心）；Institut fur Physik, Humboldt-Universität zu Berlin（柏林洪堡大学物理研究所）；Division of Physics, Mathematics, and Astronomy, California Institute of Technology（加州理工学院物理、数学和天文学系）；University of Maryland, Department of Astronomy（马里兰大学天文学系）；NASA Goddard Space Flight Center, Astrophysics Science Division（美国宇航局戈达德太空飞行中心天体物理学科学部）；Center for Research and Exploration in Space Science and Technology, NASA/GSFC（NASA/GSFC空间科学与技术研究探索中心）
