发表机构
Institute of Theoretical Astrophysics, University of Oslo; University of South Carolina; Max-Planck-Institut für Radioastronomie; Aix Marseille Univ, CNRS, CNES, LAM（奥斯陆大学理论天体物理研究所; 南卡罗来纳大学; 马克斯·普朗克射电天文研究所; 艾克斯-马赛大学，法国国家科学研究中心，法国国家空间研究中心，拉姆实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用多尺度观测数据，揭示触须星系并合中分子气体与磁场反相关及运动学特征与磁场对齐，表明小尺度结构影响大尺度偏振测量。
AI 中文摘要
重大并合事件是星系演化中的变革性过程，动态重塑了宿主星系的恒星与气体组成，以及渗透于其星际介质（ISM）中的星系尺度磁场（B场），改变了磁场强度和构型。在本工作中，我们利用APEX望远镜LAsMA接收机的CO(3-2)数据和ALMA数据，结合SOFIA/HAWC+的154微米尘埃偏振档案数据，详细研究了邻近的触须星系并合系统（NGC 4038/4039）冷星际介质相中共同演化的气体与磁场之间的联系。我们表征了分子气体强度与速度弥散测量值同APEX和SOFIA数据在千秒差距尺度上的偏振测量值之间的趋势。我们发现CO强度（ρ≲-0.6）和CO速度弥散（ρ≲-0.4）呈反相关，这是几何去偏振的标志。由于尘埃偏振测量是波束尺寸以下磁场矢量的密度加权视线积分平均，ALMA数据可以逐通道作为SOFIA波束以下密度结构的代理。通过对ALMA通道中结构的几何分析，我们在重叠区域识别出与SOFIA推断的磁场方向强烈对齐的显著运动学特征。这表明，假设分子气体结构与星系磁场之间存在对应关系，这些运动学特征可能主要将其方向赋予所测量的场方向，这归因于它们的密度或高偏振分数。我们还识别出小尺度上分子气体相干性（视线角弥散的代理）与SOFIA偏振分数之间存在适度趋势（ρ~0.5），表明在约2千秒差距尺度上测量的偏振分数对约50秒差距尺度的结构敏感。
英文摘要
Major mergers are transformative events in galaxy evolution, dynamically reshaping the stellar and gas makeup of the hosts, as well as the galaxy-scale magnetic fields (B-fields) that permeate their interstellar medium (ISM), altering both B-field strength and configuration. In this work, we study in detail the link between the co-evolving gas and B-fields in the cold ISM phase of the nearby Antennae galaxy merger (NGC 4038/4039), using CO(3-2) data from the LAsMA receiver at the APEX telescope and ALMA, together with archival 154 $μ$m dust polarization data from the SOFIA/HAWC+. We characterize trends between measurements of molecular gas intensity and velocity dispersion with polarization measurements at kpc-scales with the APEX and SOFIA data. We find anti-correlations with CO intensity ($ρ\lesssim-0.6$) and CO velocity dispersion ($ρ\lesssim-0.4$), which are signposts of geometric depolarization. Since dust polarization measurements are a density-weighted line-of-sight integrated average of B-field vectors below the beam size, the ALMA data can serve as a proxy of density structures below the SOFIA beam on a channel-by-channel basis. Through a geometric analysis of structures in the ALMA channels, we identify salient kinematic features in the overlap region strongly aligned with the SOFIA-inferred B-field orientation. This indicates that these kinematic features might dominantly lend their orientation to the measured field direction, assuming a correspondence between molecular gas structures and galactic B-fields, owing to their density or high polarization fraction. We also identify a modest trend ($ρ\sim0.5$) between the coherence of the molecular gas, a proxy of the line-of-sight angular dispersion, at small scales, and the SOFIA polarization fraction, showing that the polarization fraction measured at $\sim2$ kpc scales is sensitive to structures at $\sim50$ pc scales.
Comments15 pages, 8 figures (Submitted to Astronomy & Astrophysics, comments welcome)
