标题： 仙王座A东南区域反向喷出层的X射线研究 显示英文标题

标题： X-ray Studies of the Inverted Ejecta Layers in the Southeast Area of Cassiopeia A

摘要： 核心坍缩超新星中的强活动预计会在超新星爆炸过程中产生铁和硅/氧富集喷出物的翻转，基于多维模拟结果。卡西尼A超新星遗迹的X射线观测表明，富含铁的喷出物位于东南区域富含硅材料的外部，这与喷出物翻转的假设一致。我们详细研究了反转喷出物层的动力学和核合成特性，以利用钱德拉X射线天文台的数据理解其形成过程。通过结合视向速度和自行速度，获得铁和硅/氧富集喷出物的三维速度分别为$>$4,500 km/s$^{-1}$和$\sim$2,000–3,000 km/s$^{-1}$，表明从爆炸早期阶段起，硅/氧富集喷出物的速度就比铁富集喷出物的速度慢。为了限制它们的燃烧模式，外层铁富集区的Cr/Fe质量比被评估为$0.51_{-0.10}^{+0.11}$%，而在内层铁/硅富集区为$1.24 ^{+0.19}_{-0.20}$%，表明完全硅燃烧层反转地位于不完全硅燃烧层之上。所有结果均支持卡西尼A遗迹演化的早期阶段或其超新星爆炸期间的喷出物翻转。 显示英文摘要

摘要： The central strong activities in core-collapse supernovae expect to produce the overturning of the Fe- and Si/O-rich ejecta during the supernova explosion based on multi-dimensional simulations. X-ray observations of the supernova remnant Cassiopeia A have indicated that the Fe-rich ejecta lies outside the Si-rich materials in the southeastern region, which is consistent with the hypothesis on the inversion of the ejecta. We investigate the kinematic and nucleosynthetic properties of the inverted ejecta layers in detail to understand its formation process using the data taken by the Chandra X-ray Observatory. Three-dimensional velocities of Fe- and Si/O-rich ejecta are obtained as $>$4,500 km s$^{-1}$ and $\sim$2,000--3,000 km s$^{-1}$, respectively, by combining proper motion and line-of-sight velocities, indicating that the velocity of the Si/O-rich ejecta is slower than that of the Fe-rich ejecta since the early stage of the explosion. To constrain their burning regime, the Cr/Fe mass ratios are evaluated as $0.51_{-0.10}^{+0.11}$% in the outermost Fe-rich region and $1.24 ^{+0.19}_{-0.20}$% in the inner Fe/Si-rich region, suggesting that the complete Si burning layer is invertedly located to the incomplete Si burning layer. All the results support the ejecta overturning at the early stages of the remnant's evolution or during the supernova explosion of Cassiopeia A.