发表机构
Max Planck Institute for Extraterrestrial Physics; Laboratory for the study of the Universe and eXtreme phenomena (LUX), Observatoire de Paris; Institut de Radioastronomie Millimétrique; School of Physics and Astronomy, Cardiff University; National Radio Astronomy Observatory; INAF Osservatorio Astronomico di Arcetri（马克斯·普朗克地外物理研究所; 巴黎天文台宇宙与极端现象研究实验室（LUX）; 毫米波射电天文学研究所; 卡迪夫大学物理与天文学学院; 美国国家无线电天文台; 意大利国家天体物理研究所阿切特里天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究首次在超新星遗迹IC443和W44中探测到PO+，发现其丰度与激波强度及介质密度相关，表明超新星激波驱动离子主导的磷化学，影响分子云中磷物种的演化。
AI 中文摘要
超新星遗迹（SNR）可能塑造恒星形成的物理和化学性质。通过将难熔元素释放到气相中，它们将具有前生物相关性的物质注入分子云。这些元素可能被行星系统继承，并对生命的出现产生重要影响。我们研究了受超新星遗迹激波影响的分子云中磷（P）携带物种的存在情况。P是一种关键的生物元素，但它在分子云中的存在和储库仍然难以捉摸。我们展示了使用IRAM 30米望远镜获得的、朝向W44和IC443超新星遗迹与其相关分子云相互作用位置的高灵敏度3毫米观测结果。聚焦于PO+(2-1)和PN(2-1)，我们在局部热动平衡条件下推导了分子柱密度和丰度。我们研究了P携带物种与激波示踪剂一氧化硅（SiO）之间的相关性。我们首次在超新星遗迹中探测到PO+，其丰度X(PO+)~8e-12-5e-11，但没有显著的PN发射。朝向两个超新星遗迹的PO+与强SiO发射相关联，显示出相似的线宽但存在速度偏移，表明PO+优先示踪激波中最压缩且电离更强的层。通过将推导的丰度与文献中报道的丰度进行比较，我们提出PO+丰度主要取决于激波强度和受激波介质密度的组合。我们的结果表明，超新星遗迹激波中的P化学转向离子主导状态，这可能是由增强的宇宙射线电离率驱动的。在这种情景下，中性物种如PN被有效破坏，而离子-分子反应有利于PO+的产生。这表明超新星遗迹激波可能在处理P携带物质和塑造分子云中气相P化学方面发挥作用，对恒星形成环境的化学库存具有潜在影响。
英文摘要
Supernova remnant (SNR) may shape the physical and chemical properties of star formation. By releasing refractory elements into the gas phase, they inject material of pre-biotic relevance into molecular clouds. Such elements may be inherited by planetary systems and become relevant for the emergence of life. We investigate the presence of P-bearing species in molecular clouds impacted by SNR-shocks. P is a crucial biological element, but its presence and reservoir in molecular clouds remain elusive. We present high-sensitivity 3 mm observations obtained with the IRAM 30m, toward the interaction sites between the SNRs W44 and IC443 and their associated molecular clouds. Focusing on PO+(2-1) and PN(2-1), we derive molecular column densities and abundances in local thermodynamic equilibrium. We investigate the correlation between P-bearing species and the shock tracer Silicon Monoxide (SiO). We detect, for the first time, PO+ toward SNRs, with abundances X(PO+)~8e-12-5e-11, but no significant PN emission. PO+ toward both SNRs is associated with strong SiO emission, showing similar linewidths but velocity offsets, suggesting that PO+ preferentially traces the most compressed and more strongly ionised layers of the shock. By comparing the derived abundances with those reported in literature, we suggest that the PO+ abundance mainly depends on a combination of shock strength and shocked medium density. Our results indicate that P-chemistry in SNR shocks is shifted toward an ion-dominated regime, likely driven by enhanced cosmic-ray ionisation rates. In this scenario, neutral species such as PN are efficiently destroyed, while ion-molecule reactions favour the production of PO+. This suggests that SNR shocks may play a role in processing P-bearing material and shaping gas-phase P chemistry in molecular clouds, with potential implications for the chemical inventory of star-forming environments.
Comments14 pages, 9 figures, accepted for publication in A&A
