We report the discovery of a mid-infrared (MIR) flare using WISE data in the center of the nearby Seyfert 1.9 galaxy MCG-02-04-026. The MIR flare began in the first half of 2014, peaked around the end of 2015, and faded in 2017. During these years, energy more than $7\times10^{50}$ erg was released in the infrared, and the flare's MIR color was generally turning red. We detected neither optical nor ultraviolet (UV) variation corresponding to the MIR flare based on available data. We explained the MIR flare using a dust echo model in which the radiative transfer is involved. The MIR flare can be well explained as thermal reradiation from dust heated by UV-optical photons of a primary nuclear transient event. Although the transient event was not seen directly due to dust obscuration, we can infer that it may produce a total energy of at least $\sim10^{51}$ erg, most of which was released in less than $\sim$3 years. The nature of the transient event could be a stellar tidal disruption event by the central supermassive black hole (SMBH), or a sudden enhancement of the existing accretion flow onto the SMBH, or a supernova which was particularly bright.
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）
Revealing a multi-zone circumnuclear dust response in UGC 11487 through phase-resolved WISE W1--W2 diagnostics
Main Astronomical Observatory of the NAS of Ukraine（乌克兰国家科学院主天文台）；International Centre for Astronomical, Medical and Ecological Research（国际天文、医学与生态研究中心）
A tidal disruption event in a quasar at redshift 7.19
University of Toronto（多伦多大学）；Dunlap Institute for Astronomy and Astrophysics, University of Toronto（多伦多大学邓普天文学与天体物理研究所）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理学研究所）
