发表机构
University of Missouri – Kansas City; Jet Propulsion Laboratory, California Institute of Technology; Columbia University; Flatiron Institute; Massachusetts Institute of Technology; California Institute of Technology; American Museum of Natural History; CUNY Borough of Manhattan Community College; CUNY Graduate Center（密苏里大学堪萨斯城分校; 加州理工学院喷气推进实验室; 哥伦比亚大学; 平顿研究所; 麻省理工学院; 加州理工学院; 美国自然历史博物馆; 纽约市立学院曼哈顿社区学院; 纽约市立大学研究生中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用WISE超10年的中红外数据，识别出两个AGN中的候选TDE，发现WISE可探测尘埃遮蔽AGN中的TDE，为研究TDE提供了新途径。
AI 中文摘要
我们呈现了一项系统研究的首批成果，该研究基于广域红外巡天探测器（WISE）任务超过10年的基线数据，对活动星系的极端中红外变异性展开分析。WISE每六个月对全天进行一次观测，对消光星系和未消光星系中的暂现事件均具有探测灵敏度。本文聚焦于活动星系核（AGN）中的极端耀斑。此前的研究在非活动星系中发现了潮汐瓦解事件（TDE）等耀斑，这类发现通常来自光学或X射线巡天。然而，AGN中也应存在耀斑，而光学/X射线搜寻对尘埃遮蔽AGN中的事件并不敏感。在这项试点研究中，我们通过极端中红外颜色变异性识别出两个AGN中的耀斑，其中一个耀斑也在光学波段被探测到。尽管两个事件在耀斑峰值后数年均呈现出Hα发射线增宽，但最新光谱显示，仅带有光学耀斑的源持续存在增宽发射线。在考虑了超新星、微引力透镜等多种可能的耀斑物理成因后，我们认为这两个事件均为AGN中的TDE。值得注意的是，该光学耀斑的衰减速度远快于非活动星系中TDE预期的t^(-5/3)回落率，这表明要么是部分瓦解，要么是恒星被嵌入AGN吸积盘的中等质量黑洞潮汐瓦解。本研究证明了WISE在识别完整TDE样本（包括尘埃遮蔽AGN中的事件）方面的能力，中红外数据可探测事件本质并提供耀斑能量的热辐射测量。
英文摘要
We present first results from a systematic study of extreme mid-infrared variability of active galaxies across the $>10$-year baseline of the Wide-field Infrared Survey Explorer (WISE) mission. WISE, which observed the full sky with a six-month cadence, is sensitive to transient events in both unobscured and obscured galaxies. This paper focuses on extreme flares in active galactic nuclei (AGNs). Previous studies identified flares such as tidal disruption events (TDEs) in inactive galaxies, typically from optical or X-ray surveys. However, flares are also expected in AGN and optical/X-ray searches are insensitive to events in dust-enshrouded AGN. In this pilot study, we present flares in two AGN identified from extreme mid-infrared color variability. One flare was also detected at optical wavelengths. While both events showed broadened H$α$ emission several years after the flare peak, more recent spectroscopy reveals continued broadened emission only from the source with the optical flare. After considering several potential physical causes of the flares, including supernovae and micro-lensing, we suggest both events are TDEs in AGN. Intriguingly, the optical flare decays much faster than the expected $t^{-5/3}$ fallback rate expected for TDEs in quiescent galaxies, suggesting either a partial disruption or the tidal disruption of a star by an intermediate mass black hole embedded in the accretion disk of an AGN. This work demonstrates the power of WISE to identify the full census of TDEs, including events in dust-obscured AGN. Mid-infrared data probes the nature of the event and provides a bolometric measure of the flare energetics.
CommentsSubmitted to ApJ
