标题： 近红外观测巨质量恒星形成区AFGL 5180中的喷流和年轻恒星天体 显示英文标题

标题： Near-Infrared Observations of Outflows and YSOs in the Massive Star-Forming Region AFGL 5180

摘要： 方法：AFGL 5180的宽谱和窄谱成像在近红外波段使用LBT进行，包括在视宁度限制（$\sim0.5\arcsec$）和高角分辨率（$\sim0.09\arcsec$）自适应光学（AO）模式下，以及使用HST。还利用了存档的ALMA连续谱数据。 结果：通过H$_2$的近红外辐射和[FeII]示踪冲击气体，至少识别出40个喷流结。从中心最 massive 原恒星S4流出的明亮喷流结出现在源的东侧，并通过AO成像以精细细节解析。其他结分布在全场，可能表明存在多个驱动源。 ALMA检测到的亚毫米波源显示为两个主要复合体，AFGL 5180 M和南部一个小的集群$\sim15\arcsec$，AFGL 5180 S。从我们的近红外连续谱图像中，我们识别出质量低至$\sim 0.1\:M_\odot$的YSO候选者。 结合亚毫米波源，这得出在约0.1 pc的投影半径内，这类YSO的表面数量密度为$N_* \sim 10^3 {\rm pc}^{-2}$。这个值与来自湍流团块环境的核心吸积模型和竞争吸积模型的预测相似。 $N_*$的径向分布在0.2~pc尺度上相对平坦，在0.05~pc内的大质量原恒星内部仅有适度增强。 结论：本研究展示了高分辨率近红外成像，特别是自适应光学，在遥远区域检测喷流活动和YSO的效用。 所呈现的图像揭示了大尺度双极喷流中喷流冲击气体的复杂形态，以及该区域中其他几个喷流驱动源的明确证据。 最后，这项工作提出了一种新方法，将我们研究中观测到的YSO表面数量密度与不同的大质量恒星形成模型进行比较。 显示英文摘要

摘要： Methods: Broad- and narrow-band imaging of AFGL 5180 was made in the NIR with the LBT, in both seeing-limited ($\sim0.5\arcsec$) and high angular resolution ($\sim0.09\arcsec$) Adaptive Optics (AO) modes, as well as with HST. Archival ALMA continuum data was also utilized. Results: At least 40 jet knots were identified via NIR emission from H$_2$ and [FeII] tracing shocked gas. Bright jet knots outflowing from the central most massive protostar, S4, are detected towards the east of the source and are resolved in fine detail with the AO imaging. Additional knots are distributed throughout the field, likely indicating the presence of multiple driving sources. Sub-millimeter sources detected by ALMA are shown to be grouped in two main complexes, AFGL 5180 M and a small cluster $\sim15\arcsec$ to the south, AFGL 5180 S. From our NIR continuum images we identify YSO candidates down to masses of $\sim 0.1\:M_\odot$. Combined with the sub-mm sources, this yields a surface number density of such YSOs of $N_* \sim 10^3 {\rm pc}^{-2}$ within a projected radius of about 0.1 pc. Such a value is similar to those predicted by models of both Core Accretion from a turbulent clump environment and Competitive Accretion. The radial profile of $N_*$ is relatively flat on scales out to 0.2~pc, with only modest enhancement around the massive protostar inside 0.05~pc. Conclusions: This study demonstrates the utility of high-resolution NIR imaging, in particular with AO, for detecting outflow activity and YSOs in distant regions. The presented images reveal the complex morphology of outflow-shocked gas within the large-scale bipolar flow of a massive protostar, as well as clear evidence for several other outflow driving sources in the region. Finally, this work presents a novel approach to compare the observed YSO surface number density from our study against different models of massive star formation.