论文标题
在W33复合物周围的扩展物理系统中发现不同的环境
Uncovering distinct environments in an extended physical system around the W33 complex
论文作者
论文摘要
我们提出了包含W33复合物的大型物理系统的多波长研究。根据[29.6，60.2] km/s和88 Atlasgal 870微米尘埃团的分子气体的分布选择扩展系统（〜50 pc x 37 pc）。在13CO和C18O发射的地图中追踪的扩展系统/分子云包含OB恒星（年龄〜0.3-1.0 Myr）和热临界细丝（“ FS1”，长度〜17 PC）激发的几个HII区域。缺乏离子气体的细丝显示了〜19 K的灰尘温度（T_D），而HII区域则以〜21-29 K的t_d描绘。它表明云中存在两个不同的环境。 I级恒星物体的分布（平均年龄〜0.44 Myr）将恒星形成（SF）的早期阶段朝向云。研究了至少三个速度成分（约35、45和53 km/s）。对13CO和C18O的分析揭示了约35和53 km/s的云成分的空间和速度连接。在这两个云成分的互补分布中发现了先前已知的源W33 Main，W33 A和O4-7i星的观察到的位置。灯丝“ FS1”和先前已知的对象W33 B朝向云层的重叠区域，在云的重叠区域中，持续的SF活动是显而易见的。关于来自两个不同速度组件的收敛/碰撞流的方案似乎很好地解释了系统中SF活动的路标。
We present a multi-wavelength investigation of a large-scale physical system containing the W33 complex. The extended system (~50 pc x 37 pc) is selected based on the distribution of molecular gas at [29.6, 60.2] km/s and of 88 ATLASGAL 870 micron dust clumps at d ~2.6 kpc. The extended system/molecular cloud traced in the maps of 13CO and C18O emission contains several HII regions excited by OB stars (age ~0.3-1.0 Myr) and a thermally supercritical filament ("fs1", length ~17 pc). The filament, devoid of the ionized gas, shows dust temperature (T_d) of ~19 K, while the HII regions are depicted with T_d of ~21-29 K. It suggests the existence of two distinct environments in the cloud. The distribution of Class I young stellar objects (mean age ~0.44 Myr) traces the early stage of star formation (SF) toward the cloud. At least three velocity components (around 35, 45, and 53 km/s) are investigated toward the system. The analysis of 13CO and C18O reveals the spatial and velocity connections of cloud components around 35 and 53 km/s. The observed positions of previously known sources, W33 Main, W33 A and O4-7I stars, are found toward a complementary distribution of these two cloud components. The filament "fs1" and a previously known object W33 B are seen toward the overlapping areas of the clouds, where ongoing SF activity is evident. A scenario concerning the converging/colliding flows from two different velocity components appears to explain well the observed signposts of SF activities in the system.
