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.

中文翻译：

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活动星系中的中红外耀斑 MCG-02-04-026：核瞬态事件的尘埃回波

我们报告了使用 WISE 数据在附近的 Seyfert 1.9 星系 MCG-02-04-026 中心发现的中红外 (MIR) 耀斑。中红外耀斑开始于 2014 年上半年，在 2015 年底左右达到顶峰，并在 2017 年消退。在这些年中，超过 $7\times10^{50}$erg 的能量在红外线中被释放，并且耀斑的 MIR 颜色一般都变红了。根据可用数据，我们既未检测到与 MIR 耀斑相对应的光学或紫外线 (UV) 变化。我们使用涉及辐射传输的尘埃回波模型​​来解释 MIR 耀斑。中红外耀斑可以很好地解释为由初级核瞬变事件的紫外光光子加热的尘埃的热再辐射。虽然由于尘埃遮挡没有直接看到瞬态事件，我们可以推断它可能产生至少 $\sim10^{51}$ erg 的总能量，其中大部分是在不到 $\sim$3 年的时间内释放出来的。瞬态事件的性质可能是由中央超大质量黑洞 (SMBH) 引起的恒星潮汐破坏事件，或者是现有吸积流突然增强到 SMBH，或者是一颗特别明亮的超新星。