标题： TMC-1中更多的硫：通过QUIJOTE线状巡天发现NC$_3$S和HC$_3$S自由基 显示英文标题

标题： More sulphur in TMC-1: Discovery of the NC$_3$S and HC$_3$S radicals with the QUIJOTE line survey

摘要： 我们利用QUIJOTE线谱巡天探测到了自由基NC$_3$S和HC$_3$S在TMC-1中的存在。 导出的列密度为 (1.4$\pm$0.2)$\times$10$^{11}$对于 NC$_3$S，以及 (1.5$\pm$0.2)$\times$10$^{11}$对于 HC$_3$S。我们搜索了 NCCS，但只有三个跃迁在我们的 QUIJOTE 线状谱调查范围内，并且观测到的线仅在 3$\sigma$水平上部分检测到，给出了其列密度的一个上限为 $\leq$6$\times$10$^{10}$ cm$^{-2}$。 我们还未能在我们的 TMC-1 数据中找到更长链的 NC$_n$S（n$\ge$≥ 4）和 HC$_n$S（n$\ge$≥ 5）家族的物种。 基于涉及 HC$_3$S 和 NC$_3$S 的一组简化反应的化学模型预测的丰度比观测值低 10 到 100 倍。 这些计算表明，模型中最有效的 HC$_3$S 和 NC$_3$S 形成反应分别是 S + C$_3$H$_2$和 N + HC$_3$S，而两种自由基均通过与中性原子的反应被非常有效地去除。 显示英文摘要

摘要： We present the detection of the free radicals NC$_3$S and HC$_3$S towards TMC-1 with the QUIJOTE line survey. The derived column densities are (1.4$\pm$0.2)$\times$10$^{11}$ for NC$_3$S and (1.5$\pm$0.2)$\times$10$^{11}$ for HC$_3$S. We searched for NCCS, but only three transitions are within the domain of our QUIJOTE line survey and the observed lines are marginally detected at the 3$\sigma$ level, providing an upper limit to its column density of $\leq$6$\times$10$^{10}$ cm$^{-2}$. We also unsuccessfully searched for longer species of the NC$_n$S (n$\ge$4) and HC$_n$S (n$\ge$5) families in our TMC-1 data. A chemical model based on a reduced set of reactions involving HC$_3$S and NC$_3$S predicts abundances that are 10-100 times below the observed values. These calculations indicate that the most efficient reactions of formation of HC$_3$S and NC$_3$S in the model are S + C$_3$H$_2$ and N + HC$_3$S, respectively, while both radicals are very efficiently destroyed through reactions with neutral atoms.