We present the first detection in space of thionylimide (HNSO) toward the Galactic center molecular cloud G + 0.693-0.027, thanks to the superb sensitivity of an ultradeep molecular line survey carried out with the Yebes 40 m and IRAM 30 m telescopes. This molecule is the first species detected in the interstellar medium containing, simultaneously, N, S, and O. We have identified numerous K _a = 0, 1, and 2 transitions belonging to HNSO covering from J _up = 2 to J _up =10, including several completely unblended features. We derive a molecular column density of N = (8 ± 1)×10¹³ cm⁻², yielding a fractional abundance relative to H₂ of ∼6 × 10⁻¹⁰, which is about ∼37 and ∼4.8 times less abundant than SO and SO₂, respectively. Although there are still many unknowns in the interstellar chemistry of NSO-bearing molecules, we propose that HNSO is likely formed through the reaction of the NSO radical and atomic H on the surface of icy grains, with alternative routes also deserving exploration. Finally, HNSO appears as a promising link between N, S, and O interstellar chemistry, and its discovery paves the route to the detection of a new family of molecules in space.

中文翻译：

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在太空中发现亚硫酰亚胺 (HNSO)：第一个含 N、S 和 O 的星际分子

得益于使用 Yebes 40 m 和 IRAM 30 m 望远镜进行的超深分子线勘测的卓越灵敏度，我们首次在太空中探测到了银河系中心分子云 G + 0.693-0.027 的亚硫酰亚胺 (HNSO)。该分子是在同时含有 N、S 和 O 的星际介质中检测到的第一个物质。我们已经鉴定出许多K _A = 0、1 和 2 属于 HNSO 的跃迁，覆盖范围为J _向上= 2 至J _up =10，包括几个完全未混合的特征。我们得出分子柱密度为氮= (8 ± 1)×10 ¹³ cm ^{-2 ，相对于 H} _{2 的}丰度分数为 ∼6 × 10 ^-10，分别比 SO 和 SO ₂丰度低约 ∼37 和 ∼4.8 倍。尽管含 NSO 分子的星际化学仍存在许多未知数，但我们认为 HNSO 很可能是通过 NSO 自由基与冰晶颗粒表面的原子 H 反应形成的，其他途径也值得探索。最后，HNSO 似乎是 N、S 和 O 星际化学之间有希望的联系，它的发现为探测太空中的新分子家族铺平了道路。