We report a new period mid-infrared variability of PMN J0948+0022 on 2020 April 26, observed by the Wide-field Infrared Survey Explore (WISE). This source faded consistently over a period of one day. The amplitude of variability is about 0.21 and 0.18 mag in the W1 (3.4 μm) and W2 (4.6 μm) bands, respectively. The intraday variability constrains the size of the mid-infrared emission region to about 5נ10⁻⁴pc, which is rather smaller than that of the dust torus but consistent with the base of a jet. The mid-infrared color showed a significant bluer-when-brighter trend, similar to γ-ray emitting blazars. These characteristics suggest that the mid-infrared emission was dominated by the synchrotron emission of relativistic electrons in the jet.

我们报告了 2020 年 4 月 26 日 PMN J0948+0022 的新时期中红外变异，由广域红外勘测探索 (WISE) 观测到。在一天的时间里，这个来源一直在消失。W1 (3.4 μ m) 和 W2 (4.6 μ m) 波段的变异幅度分别约为 0.21 和 0.18 mag 。日内变化将中红外发射区域的大小限制在 5נ10 ^-4 pc 左右，这比尘埃环面的小很多，但与喷流的底部一致。中红外颜色呈现显着的越亮越蓝趋势，类似于γ-射线发射耀变体。这些特征表明，中红外发射主要是射流中相对论电子的同步辐射。