We present comprehensive spectroscopic and photometric analyses of the intermediate luminosity type Iax supernova (SN Iax) 2019muj based on multi-band datasets observed through the framework of the OISTER target-of-opportunity program. SN 2019muj exhibits almost identical characteristics to the subluminous SNe Iax 2008ha and 2010ae in terms of the observed spectral features and the light curve evolution at the early phase, except for the peak luminosity. The long-term observations unveil late-time flattening light curves as seen in luminous SN Iax 2014dt. This can be explained by the existence of an inner dense and optically thick component possibly associated with a bound white dwarf remnant left behind after the explosion. We demonstrate that the weak deflagration model with a wide range of explosion parameters can reproduce the late-phase light curves of other SNe Iax. Therefore, we conclude that a common explosion mechanism operates for different subclass SNe Iax.

中文翻译：

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具有窄吸收线的中光度 Iax 超新星 2019muj：与弱爆燃模型预测的可能束缚残余物相关的持久辐射

我们基于通过 OISTER 机会目标计划框架观察到的多波段数据集，对中光度 Iax 超新星 (SN Iax) 2019muj 进行了全面的光谱和光度分析。SN 2019muj 在观测到的光谱特征和早期的光变曲线演变方面，除了峰值光度外，表现出与亚光度 SNe Iax 2008ha 和 2010ae 几乎相同的特征。长期观测揭示了在发光的 SN Iax 2014dt 中看到的后期变平光曲线。这可以通过内部致密且光学厚的成分的存在来解释，这可能与爆炸后留下的束缚白矮星残骸有关。我们证明了具有广泛爆炸参数的弱爆燃模型可以再现其他 SNe Iax 的后期光变曲线。因此，我们得出结论，一个共同的爆炸机制适用于不同的子类 SNe Iax。