论文标题
沿径向切割的分子线比诊断和螺旋星系NGC中的灰尘紫外线团块0628
Molecular Line Ratio Diagnostics Along the Radial Cut and Dusty UV-bright Clumps in a Spiral Galaxy NGC 0628
论文作者
论文摘要
分子发射线是在许多有关星系中恒星形成的问题的灯光的基本工具。多个分子线对于探测恒星形成分子云的不同阶段特别有用。在这项研究中，我们使用多个CO（即CO（1-0、2-1、3-2）和$^{13} $ CO（1-0）的CO（1-0、2-1、3-2）和$^{1-0）研究巨型分子云（GMC）的物理特性，在选定的20个位置在NGC 0628的光盘中获得了20个位置。在NGC 0628的光盘中，选择了NINE的位置，包括Nine Chut，Nine Sertrals nine sermern serners nine nine nine nine serm nine nine nine nine nine nine serm nine serm nine serm nine serm nine， 星系。与表明相反特征的其余位置相比，在24micron和紫外线（UV）发射时，20个位置中有13个更明亮，并且托管更大的HII区域。我们的线比分析表明，气体随着半径的函数从星系中心升至1.7 kpc，然后比率开始波动。我们的经验和模型结果表明，紫外线的位置具有较冷，更薄的CO气体，具有较高的氢和CO柱密度。但是，UV-DIM位置具有相对较高的CO气体，其密度较低，在GMC中沐浴，周围的HII区域数量较少。对多波长红外和紫外线数据的分析表明，紫外线位置的恒星形成效率高于UV-DIM位置。
Molecular emission lines are essential tools to shed lights on many questions regarding star formation in galaxies. Multiple molecular lines are particularly useful to probe different phases of star-forming molecular clouds. In this study, we investigate the physical properties of giant molecular clouds (GMCs) using multiple lines of CO, i.e. CO(1-0, 2-1, 3-2) and $^{13}$CO(1-0), obtained at selected 20 positions in the disc of NGC 0628. Eleven positions were selected over the radial cut, including the centre, and remaining nine positions were selected across the southern and northern arms of the galaxy. 13 out of 20 positions are brighter at 24micron and ultraviolet (UV) emission and hosting significantly more HII regions compared to the rest of the positions indicating opposite characteristics. Our line ratio analysis shows that the gas gets warmer and thinner as a function of radius from the galaxy centre up to 1.7 kpc, and then the ratios start to fluctuate. Our empirical and model results suggest that the UV-bright positions have colder and thinner CO gas with higher hydrogen and CO column densities. However, the UV-dim positions have relatively warmer CO gas with lower densities bathed in GMCs surrounded by less number of HII regions. Analysis of multi-wavelength infrared and UV data indicates that the UV-bright positions have higher star formation efficiency than that of the UV-dim positions.
