AI 中文总结
本研究基于MWISP巡天数据识别57个近邻宁静CO结构，发现面纱云是其重要组分，揭示其起源于本地泡超新星压缩，对恒星形成初始条件等有重要意义。
AI 中文摘要
利用银河成像巡天扫描测绘（MWISP）调查第一阶段的CO数据，我们对具有窄谱线的分子结构开展了系统研究。我们共识别出57个CO结构，其中多数呈现低密度及亚声速/跨声速湍流特征。这些结构中，投影面积大、形态弥散呈薄片状的被归类为面纱云。这些CO结构的低LSR速度，以及它们向银心（如蛇夫座、天鹰座）和反银心（如仙王座、金牛座）区域聚集的特征，表明样本具有本地起源，部分角范围较大的结构距离测量约为200-300pc，支持了这一结论。这些近邻结构可能源于本地泡内过往超新星活动驱动的大尺度压缩。观测到的低速度弥散发射可能示踪湍流因缺乏持续能量注入而衰减的宁静区域。对于假设磁场约为10uG的弥散面纱云，离子-中性粒子摩擦可能在对应其厚度0.1-0.3pc的亚秒差距尺度上提供湍流耗散的额外机制。面纱云示踪原子-分子转变过程，为致密气体的弥散、宁静前驱态提供了独特的观测窗口。它们可能代表了银河系分子气体库中广泛存在但此前被忽视的组分，对云的形成与演化、分子气体的总质量预算及空间分布，以及作为相关结果的恒星形成初始条件具有重要意义。
英文摘要
Using CO data from Phase I of the Milky Way Imaging Scroll Painting (MWISP) survey, we present a systematic study of molecular structures with narrow lines. We identify 57 CO structures, most of which exhibit low densities and subsonic/transonic turbulence. Among them, structures with large projected areas and diffuse, sheet-like geometries are identified as veil clouds. The low LSR velocities and the concentration of these CO structures toward both the Galactic center (e.g., Ophiuchus, Aquila) and anticenter (e.g., Cepheus, Taurus) regions suggest a local origin for the sample, as supported by distance measurements of about 200--300pc for a subset with relatively large angular extents. These nearby structures likely arise from large-scale compression driven by past supernova activity within the Local Bubble. The observed low-velocity-dispersion emission may trace quiescent regions where turbulence has decayed due to a lack of sustained energy injection. For diffuse veil clouds with an assumed magnetic field of ~10uG, ion-neutral friction may provide an additional mechanism for turbulent dissipation on sub-parsec scales corresponding to their thickness of 0.1--0.3pc. Tracing the atomic-to-molecular transition, veil clouds provide a unique window into the diffuse, quiescent precursor state of dense gas. They likely represent a widespread but previously overlooked component of the Galactic molecular gas reservoir, with significant implications for cloud formation and evolution, the total mass budget and spatial distribution of molecular gas, and the initial conditions of star formation as a related consequence.
Comments17 pages, 6 figures, 1 table, Accepted for publication in ApJL
Journal refThe ApJL, 1007:L21 (12pp), 2026 August 10
