The recently discovered Pa 30 nebula, the putative type Iax supernova remnant associated with the historical supernova of 1181 AD, shows puzzling characteristics that make it unique among known supernova remnants. In particular, Pa 30 exhibits a complex morphology, with a unique radial and filamentary structure, and it hosts a hot stellar remnant at its center, which displays oxygen-dominated, ultrafast winds. Because of the surviving stellar remnant and the lack of hydrogen and helium in its filaments, it has been suggested that Pa 30 is the product of a failed thermonuclear explosion in a near- or super-Chandrasekhar white dwarf, which created a subluminous transient, a rare subtype of the Ia class of supernovae called type Iax. We present here a detailed study of the 3D structure and velocities of a full radial section of the remnant. The Integral Field Unit observations, obtained with the new red channel of the Keck Cosmic Web Imager spectrograph, reveal that the ejecta are consistent with being ballistic, with velocities close to the free-expansion velocity. Additionally, we detect a large cavity inside the supernova remnant and a sharp inner edge to the filamentary structure, which coincides with the outer edge of a bright ring detected in infrared images. Finally, we detect a strong asymmetry in the amount of ejecta along the line of sight, which might hint at an asymmetric explosion. Our analysis provides strong confirmation that the explosion originated from SN 1181.

中文翻译：

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年轻的超新星型 Iax 残余物 Pa 30 的膨胀特性揭晓


最近发现的 Pa 30 星云，即与公元 1181 年的历史超新星相关的推定类型的 Iax 超新星遗迹，显示出令人费解的特征，使其在已知的超新星遗迹中独树一帜。特别是，Pa 30 表现出复杂的形态，具有独特的径向和丝状结构，并且其中心有一颗热恒星残骸，显示出以氧为主的超快风。由于幸存的恒星残骸及其细丝中缺乏氢和氦，有人认为 Pa 30 是近钱德拉塞卡白矮星或超钱德拉塞卡白矮星热核爆炸失败的产物，它产生了亚光瞬态，这是 Ia 类超新星的一种罕见亚型，称为 Iax型。我们在这里详细研究了残余物完整径向截面的 3D 结构和速度。使用 Keck Cosmic Web Imager 光谱仪的新红色通道获得的积分场单元观测表明，喷射物与弹道一致，速度接近自由膨胀速度。此外，我们在超新星残余物内部检测到一个大空腔和细丝结构的尖锐内边缘，这与红外图像中检测到的亮环的外边缘相吻合。最后，我们检测到沿视线的喷射物数量存在很强的不对称性，这可能暗示了不对称的爆炸。我们的分析有力地证实了爆炸起源于 SN 1181。