High-resolution X-ray spectra show near-solar abundances of chromium, manganese and nickel with respect to iron in the Perseus cluster, suggesting that the progenitors of type Ia supernovae could be near- and sub-Chandrasekhar-mass white dwarfs. Clusters of galaxies are embedded in hot gas, the elemental abundances of which arise from the cumulative effects of all of the supernovae that have occurred in the galaxies over the life of the cluster. Recent work found that these abundances were different from the solar ones, suggesting that the history of supernovae in the clusters diverged from what is seen in the Milky Way. However, limitations of the instruments made these observations difficult. Hiroya Yamaguchi and the rest of the Hitomi Collaboration now report very high-spectral-resolution observations of the Perseus cluster that reveal near-solar abundance ratios of elements near the iron peak. They conclude that a mixture of near- and sub-Chandrasekhar-mass white dwarfs contributed those elements through type Ia supernova explosions. The metal abundance of the hot plasma that permeates galaxy clusters represents the accumulation of heavy elements produced by billions of supernovae1. Therefore, X-ray spectroscopy of the intracluster medium provides an opportunity to investigate the nature of supernova explosions integrated over cosmic time. In particular, the abundance of the iron-peak elements (chromium, manganese, iron and nickel) is key to understanding how the progenitors of typical type Ia supernovae evolve and explode2,3,4,5,6. Recent X-ray studies of the intracluster medium found that the abundance ratios of these elements differ substantially from those seen in the Sun7,8,9,10,11, suggesting differences between the nature of type Ia supernovae in the clusters and in the Milky Way. However, because the K-shell transition lines of chromium and manganese are weak and those of iron and nickel are very close in photon energy, high-resolution spectroscopy is required for an accurate determination of the abundances of these elements. Here we report observations of the Perseus cluster, with statistically significant detections of the resonance emission from chromium, manganese and nickel. Our measurements, combined with the latest atomic models, reveal that these elements have near-solar abundance ratios with respect to iron, in contrast to previous claims. Comparison between our results and modern nucleosynthesis calculations12,13,14 disfavours the hypothesis that type Ia supernova progenitors are exclusively white dwarfs with masses well below the Chandrasekhar limit (about 1.4 times the mass of the Sun). The observed abundance pattern of the iron-peak elements can be explained by taking into account a combination of near- and sub-Chandrasekhar-mass type Ia supernova systems, adding to the mounting evidence that both progenitor types make a substantial contribution to cosmic chemical enrichment5,15,16.

中文翻译：

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Perseus星团中铁峰元素的太阳丰度比

高分辨率 X 射线光谱显示，相对于英仙座星团中的铁，铬、锰和镍的丰度接近太阳，这表明 Ia 型超新星的祖先可能是接近和亚钱德拉塞卡质量的白矮星。星系团嵌入在热气体中，其元素丰度来自星系团生命周期中发生在星系中的所有超新星的累积效应。最近的工作发现，这些丰度与太阳的丰度不同，这表明星团中超新星的历史与银河系中看到的不同。然而，仪器的局限性使这些观察变得困难。Hiroya Yamaguchi 和 Hitomi Collaboration 的其他成员现在报告了对英仙座星团的非常高光谱分辨率的观测，揭示了铁峰附近元素的近太阳丰度比。他们得出结论，近和亚钱德拉塞卡质量白矮星的混合物通过 Ia 型超新星爆炸贡献了这些元素。渗透星系团的热等离子体的金属丰度代表了数十亿颗超新星产生的重元素的积累。因此，星团内介质的 X 射线光谱为研究超新星爆炸在宇宙时间上的综合性质提供了机会。特别是，铁峰元素（铬、锰、铁和镍）的丰度是了解典型 Ia 型超新星的祖先如何演化和爆炸的关键 2,3,4,5,6。最近对星团内介质的 X 射线研究发现，这些元素的丰度比与在太阳 7、8、9、10、11 中看到的有很大不同，这表明星团和银河系中 Ia 型超新星的性质存在差异办法。然而，由于铬和锰的 K 壳过渡线很弱，而铁和镍的 K 壳过渡线在光子能量上非常接近，因此需要高分辨率光谱来准确测定这些元素的丰度。在这里，我们报告了对 Perseus 星团的观察结果，对铬、锰和镍的共振发射进行了统计上显着的检测。我们的测量与最新的原子模型相结合，表明这些元素与铁的丰度比接近太阳，与之前的说法相反。我们的结果与现代核合成计算 12,13,14 之间的比较不支持 Ia 型超新星前身完全是质量远低于钱德拉塞卡极限（大约是太阳质量的 1.4 倍）的白矮星的假设。观察到的铁峰元素的丰度模式可以通过考虑近和亚钱德拉塞卡质量 Ia 型超新星系统的组合来解释，这增加了越来越多的证据表明这两种类型的祖先都对宇宙化学富集做出了重大贡献 5 ,15,16。