超新星遗迹与分子云作用过程的多波段研究

The environments surrounding supernova remnants (SNRs) could be highly asymmetric and inhomogeneous, due to the strong modification of the massive progenitor star and the intrinsic inhomogeneity of the interstellar medium (ISM). Furthermore, The interactions between SNRs and the surrounding dense molecular gas involve many non-linear physical processes (e.g., saturated thermal conduction, molecular chemical reaction, etc.), which complicate the understanding of SNR evolution. However, these widespread phenomena also provide basic knowledges of widespread shocks in multiphase ISM at the same time. We intend to use the survey data of CO molecular emission lines observed by 13.7m radio telescope of the Purple Mountain Observatory at Qinghai observation station to examine the associations and interactions between SNRs and molecular clouds (MCs). Then, we will select several typical cases of interactions between SNRs and MCs, and observe them by mapping in multiple molecular emission lines. Combining multiband archive data, we will make a thorough observational study. In this work, new cases of interactions between SNRs and MCs will be found, which are with different morphologies and in different evolutional stages. Our knowledge on the physical and chemical structure of molecular gas in the interaction regions will be enriched. On the other hand, based on the observational results, we will also apply numerical simulation for further theoretical analysis, aiming to understand the roles of non-linear physical processes, such as thermal conduction and non-equilibrium ionization process, in SNR evolution, especially, the origin of overionized plasma in SNR. We aim to thoroughly understand several typical cases of the interactions between SNRs and MCs, to make our contribution on fully understanding the evolution of the SNRs interacting with MCs.

超新星遗迹周围环境的复杂性以及遗迹与致密分子气体相互作用涉及的多种复杂过程（包括饱和热传导和分子化学过程），是理解超新星遗迹演化的主要困难，这种情形具有普遍性，也是理解星际介质中多种激波过程的契机。本项目包含两个方面，首先，从观测上，将利用紫金山天文台青海观测站13.7米毫米波望远镜的CO分子谱线巡天数据，发挥优势观测条件，对遗迹与分子云的相互作用进行认证，选出有代表性的样本进行多分子谱线联合观测，结合已有的多波段数据作深入分析。此项工作将认证出不同形态与演化阶段的遗迹与分子云的相互作用过程，丰富对作用区分子气体的物理和化学结构的认识。然后，将基于观测结果，建立数值模型进行理论分析，深入探讨热传导、非电离平衡等非线性物理过程在遗迹演化中所起到的作用，讨论遗迹中过电离等离子体的起源。我们期待比较透彻的了解几个有代表性的遗迹与分子云相互作用情形，为全面理解复杂环境中超新星遗迹的演化作出贡献。

超新星遗迹会释放大量的能量和金素元素到星际介质中，是恒星形成过程和星系形成和演化的关键一环，对其在非均匀介质中的演化是当今国际天体物理学的前沿领域，其中热混合型超新星遗迹和遗迹中过电离气体的起源都对现有理论模型提出了挑战。本项目针对非均匀环境中超新星遗迹的演化，首先，从观测上，利用紫金山天文台青海观测站13.7米毫米波望远镜的CO分子谱线巡天数据，发挥优势观测条件，认证出了新的不同形态与演化阶段的多个遗迹与分子云的相互作用，得到了这些遗迹周围分子气体的分布情况，并结合已有的多波段数据进行了深入分析，得到了多个超新星遗迹与分子云相互作用的物理细节和遗迹的演化状态。这些观测结果，丰富了对遗迹周围气体环境和激波作用区中分子气体物理状态的认识，为进一步的统计研究准备了条件。另一方面，我们基于最新的原子数据库ATOMDB v3.0.9，研究了在非均匀介质中演化的超新星遗迹中非电离平衡等离子体的辐射特性，对已有理论分析手段进行了完善，包括：了解非电离平衡等离子体的普遍的辐射特性，建立非电离平衡等离子体辐射率表，让我们能够在数值模型中考虑更实际的非电离平衡等离子体的辐射冷却反馈；合成数值模型的非电离平衡等离子体辐射谱，进而与X射线观测直接比对，得到对遗迹中热气体演化过程更深入、细致的理解。本研究增进了对不同情形超新星遗迹与分子云相互作用的理解，扩大了相互作用的样本，并深入探讨了超新星遗迹中热气体的电离和辐射冷却过程，为全面理解复杂环境中超新星遗迹的演化作出了一定的贡献。