Title: The dynamical properties of dense filaments in the infrared dark cloud G035.39-00.33 Show Chinese title

Title: G035.39-00.33红外暗云中密集纤维的动力学特性

Abstract: Infrared Dark Clouds (IRDCs) are unique laboratories to study the initial conditions of high-mass star and star cluster formation. We present high-sensitivity and high-angular resolution IRAM PdBI observations of N2H+ (1-0) towards IRDC G035.39-00.33. It is found that G035.39-00.33 is a highly complex environment, consisting of several mildly supersonic filaments (sigma_NT/c_s ~1.5), separated in velocity by <1 km s^-1 . Where multiple spectral components are evident, moment analysis overestimates the non-thermal contribution to the line-width by a factor ~2. Large-scale velocity gradients evident in previous single-dish maps may be explained by the presence of substructure now evident in the interferometric maps. Whilst global velocity gradients are small (<0.7 km s^-1 pc^-1), there is evidence for dynamic processes on local scales (~1.5-2.5 km s^-1 pc^-1 ). Systematic trends in velocity gradient are observed towards several continuum peaks. This suggests that the kinematics are influenced by dense (and in some cases, starless) cores. These trends are interpreted as either infalling material, with accretion rates ~(7 \pm 4)x10^-5 M_sun yr^-1 , or expanding shells with momentum ~24 \pm 12 M_sun km s^-1 . These observations highlight the importance of high-sensitivity and high-spectral resolution data in disentangling the complex kinematic and physical structure of massive star forming regions. Show Chinese abstract

Abstract: 红外暗云（IRDCs）是研究大质量恒星和星团形成初始条件的独特实验室。 我们展示了对IRDC G035.39-00.33的N2H+ (1-0)的高灵敏度和高角分辨率IRAM PdBI观测。 发现G035.39-00.33是一个高度复杂的环境，由几个轻微超音速的丝状结构（sigma_NT/c_s ~1.5）组成，这些结构在速度上被<1 km s^-1 分离。 当存在多个光谱成分时，通过矩分析会高估线宽中非热贡献的幅度约2倍。 先前单天线地图中显示的大尺度速度梯度可能由干涉测量地图中现在显现的子结构解释。 尽管全局速度梯度较小（<0.7 km s^-1 pc^-1），但在局部尺度上存在动态过程的证据（~1.5-2.5 km s^-1 pc^-1）。 在多个连续谱峰方向观察到速度梯度的系统性趋势。 这表明动力学受到密集（在某些情况下，无恒星）核心的影响。 这些趋势被解释为吸积率约为(7\pm 4)x10^-5 M_sun yr^-1 的下落物质，或者动量约为24\pm 12 M_sun km s^-1 的膨胀壳层。 这些观测结果突显了高灵敏度和高光谱分辨率数据在解析大质量恒星形成区域复杂动力学和物理结构中的重要性。