Title: Anisotropy in the carbon monoxide (CO) line emission across the Milky Way's disk Show Chinese title

Title: 银河系盘中一氧化碳（CO）线发射的各向异性

Abstract: We present a study of the $^{12}$CO(1-0) line emission anisotropy across the Milky Way's disk to examine the effect of stellar feedback and Galactic dynamics on the distribution of the dense interstellar medium. The Hessian matrix method is used to characterize the CO line emission distribution and identify the preferential orientation across line-of-sight velocity channels in the Dame et al. 2001 composite Galactic plane survey, which covers the Galactic latitude range $|b|<5^{\circ}$. The structures sampled with this tracer are predominantly parallel to the Galactic plane toward the inner Galaxy, in clear contrast with the predominantly perpendicular orientation of the structures traced by neutral atomic hydrogen (HI) emission toward the same regions. The analysis of the Galactic plane portions sampled at higher angular resolution with other surveys reveals that the alignment with the Galactic plane is also prevalent at smaller scales. We find no preferential orientation in the CO emission toward the outer Galaxy, in contrast with the preferential alignment with the Galactic plane displayed by HI in that portion of the Milky Way. We interpret these results as the combined effect of the decrease in mid-plane pressure with increasing Galactocentric radius and SN feedback lifting diffuse gas more efficiently than dense gas off the Galactic plane. Show Chinese abstract

Abstract: 我们研究了银河系盘中$^{12}$CO(1-0)线发射的各向异性，以考察恒星反馈和银河系动力学对致密星际介质分布的影响。 使用Hessian矩阵方法来表征CO线发射分布，并在Dame等人2001年的综合银河系平面调查中识别视线速度通道中的优选方向，该调查覆盖了银河纬度范围$|b|<5^{\circ}$。 使用此示踪剂采样的结构在内银河区域主要平行于银河平面，这与由中性原子氢（HI）发射示踪的相同区域的结构主要垂直的方向形成明显对比。 对其他调查在更高角分辨率下采样的银河平面部分进行分析显示，与银河平面的对齐在更小尺度上也普遍存在。 我们在外银河区域的CO发射中没有发现优选方向，这与银河系该部分HI表现出的与银河平面的优选对齐形成对比。 我们把这些结果解释为随着银河中心半径增加，中平面压力减小以及超新星反馈更有效地将弥散气体而非致密气体从银河平面上抬升的综合效应。