最年轻的银河系超新星遗迹G1 .9+0.3中的放射性钪
Radioactive Scandium in the Youngest Galactic Supernova Remnant G1.9+0.3
摘要：
我们报告发现的热X射线发射从最年轻的银河系超新星遗迹G1.9+0.3，从237-KS钱德拉观测。我们检测到强K壳线的Si，S，Ar，Ca和Fe。此外，我们检测到一个4.1千电子伏线与99.971%的置信度，我们归因于44 Sc，从44 Ti的电子捕获产生的。结合我们早期的钱德拉观测数据，我们可以独立地在两个区域检测到这条线。对于100年的残余年龄，我们测量的总谱线强度表明合成的$(1 - 7) \times 10^{-5}$太阳质量为44 Ti，在Ia型和核心坍缩超新星的预测范围内，但略小于Cas A报告的$2 \times 10^{-4}$太阳质量。线光谱显示了超太阳的丰度。Fe辐射的宽度约为28，000 km/s，与大约100年的年龄和推断的平均激波速度14，000 km/s（假设距离为8.5 kpc）相一致。大多数热辐射来自X射线较低但射电表面亮度较高的区域。更深入的观察应该允许更详细的空间映射钪，具有显着的影响，在Ia型超新星的核合成模型。
英文摘要：
We report the discovery of thermal X-ray emission from the youngest Galactic supernova remnant G1.9+0.3, from a 237-ks Chandra observation. We detect strong K-shell lines of Si, S, Ar, Ca, and Fe. In addition, we detect a 4.1 keV line with 99.971% confidence which we attribute to 44Sc, produced by electron capture from 44Ti. Combining the data with our earlier Chandra observation allows us to detect the line in two regions independently. For a remnant age of 100 yr, our measured total line strength indicates synthesis of $(1 - 7) \times 10^{-5}$ solar masses of 44Ti, in the range predicted for both Type Ia and core-collapse supernovae, but somewhat smaller than the $2 \times 10^{-4}$ solar masses reported for Cas A. The line spectrum indicates supersolar abundances. The Fe emission has a width of about 28,000 km/s, consistent with an age of about 100 yr and with the inferred mean shock velocity of 14,000 km/s deduced assuming a distance of 8.5 kpc. Most thermal emission comes from regions of lower X-ray but higher radio surface brightness. Deeper observations should allow more detailed spatial mapping of scandium, with significant implications for models of nucleosynthesis in Type Ia supernovae.
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