We present initial results from a James Webb Space Telescope (JWST) survey of the youngest Galactic core-collapse supernova remnant, Cassiopeia A (Cas A), made up of NIRCam and MIRI imaging mosaics that map emission from the main shell, interior, and surrounding circumstellar/interstellar material (CSM/ISM). We also present four exploratory positions of MIRI Medium Resolution Spectrograph integral field unit spectroscopy that sample ejecta, CSM, and associated dust from representative shocked and unshocked regions. Surprising discoveries include (1) a weblike network of unshocked ejecta filaments resolved to ∼0.01 pc scales exhibiting an overall morphology consistent with turbulent mixing of cool, low-entropy matter from the progenitor’s oxygen layer with hot, high-entropy matter heated by neutrino interactions and radioactivity; (2) a thick sheet of dust-dominated emission from shocked CSM seen in projection toward the remnant’s interior pockmarked with small (∼1″) round holes formed by ≲0.″1 knots of high-velocity ejecta that have pierced through the CSM and driven expanding tangential shocks; and (3) dozens of light echoes with angular sizes between ∼0.″1 and 1′ reflecting previously unseen fine-scale structure in the ISM. NIRCam observations place new upper limits on infrared emission (≲20 nJy at 3 μm) from the neutron star in Cas A’s center and tightly constrain scenarios involving a possible fallback disk. These JWST survey data and initial findings help address unresolved questions about massive star explosions that have broad implications for the formation and evolution of stellar populations, the metal and dust enrichment of galaxies, and the origin of compact remnant objects.

中文翻译：

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JWST 对超新星遗迹仙后座 A 的巡天

我们展示了詹姆斯·韦伯太空望远镜 (JWST) 对最年轻的银河系核心塌陷超新星遗迹仙后座 A (Cas A) 进行调查的初步结果，该遗迹由 NIRCam 和 MIRI 成像镶嵌图组成，绘制了主壳、内部和外部的发射图。周围星周/星际物质（CSM/ISM）。我们还提出了 MIRI 中分辨率摄谱仪积分场单元光谱学的四个探索位置，这些位置对来自代表性冲击和未冲击区域的喷射物、CSM 和相关灰尘进行了采样。令人惊讶的发现包括（1）由未受冲击的喷出物细丝组成的网状网络，分辨率为〜0.01 pc尺度，表现出与来自祖细胞氧层的冷、低熵物质与中微子相互作用加热的热、高熵物质的湍流混合一致的整体形态。和放射性； （2）从冲击的 CSM 中看到的厚厚的以灰尘为主的排放物，在向残骸内部的投影中看到，上面有由 ≲0.”1 节的高速喷射物穿过 CSM 形成的小（~1”）圆孔。并驱动扩大的切向激波； (3)数十个角度大小在～0.″1和1′之间的光回波，反映了ISM中以前未见过的精细尺度结构。 NIRCam 观测结果对红外发射设定了新的上限（≲20 nJy at 3μm) 来自 Cas A 中心的中子星，并严格限制涉及可能的后备盘的场景。这些 JWST 调查数据和初步发现有助于解决有关大质量恒星爆炸的未解决问题，这些问题对恒星族群的形成和演化、星系的金属和尘埃富集以及致密残余物体的起源具有广泛的影响。