发表机构
University of California San Diego; University of Maryland; Joint Space-Science Institute; Princeton University; University of Toledo; Universität Heidelberg; University of Kansas; University of Pittsburgh（加州大学圣地亚哥分校; 马里兰大学; 空间科学联合研究所; 普林斯顿大学; 托莱多大学; 海德堡大学; 堪萨斯大学; 匹兹堡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用JWST/MIRI光谱的PAH特征分析M82和NGC 253的尘埃运动学，发现PAH在外流底部与电离气体更相关，且6.2微米PAH显示更高外流速度，暗示优先电离。
AI 中文摘要
我们利用JWST/MIRI光谱观测到的多环芳烃（PAH）特征，对本地星暴星系M82（NGC 3034）和NGC 253中的尘埃运动学进行了分析。我们成功制作了5.2微米、6.2微米和11.3微米PAH特征的高质量速度图，以及通过H₂转动跃迁得到的众多分子气体谱线和来自[NeII]及氢复合线的电离气体谱线。考虑到视场和倾角，我们在M82中追踪到一个旋转盘，观察到速度先急剧上升后趋于平缓，这是星系旋转曲线的典型特征。然而，在NGC 253中，6.2微米和11.3微米PAH特征追踪了外流的发射区域，该区域严格位于星暴区域内。我们发现电离气体在NGC 253中也显示出外流的贡献，而暖分子气体则主要受旋转支配。此外，分子气体的外流速度低于电离气体，其中11.3微米PAH特征与电离气体而非分子气体一致。因此，我们认为在星系外流底部，PAH与电离气体的关联更紧密，而非与分子气体，更大尺度的成像显示PAH与中性氢（HI）的形态相似。6.2微米PAH特征在两个星系中都具有更高的外流速度，这可能表明在外流底部运动更快的热相中，PAH被优先电离。
英文摘要
We present an analysis of dust kinematics in the local starburst galaxies M82 (NGC 3034) and NGC 253 using Polycyclic Aromatic Hydrocarbon (PAH) features observed with JWST/MIRI spectroscopy. We are able to produce high-quality velocity maps of the 5.2 $μ$m, 6.2 $μ$m, and 11.3 $μ$m PAH features, as well as numerous lines of molecular gas via H$_2$ rotational transitions and ionized gas from [NeII] and H recombination lines. Given the field of view and inclination, we trace a rotating disk in M82 where we observe a steep rise in the velocities followed by flattening, typical of galaxy rotation curves. In NGC 253, however, the 6.2 $μ$m and 11.3 $μ$m PAH features trace the launching region of the outflow, firmly within the starburst region. We find the ionized gas also shows outflow contributions in NGC 253 while the warm molecular gas is dominated by rotation. Additionally, the molecular gas outflow velocities are lower than the ionized gas, with the 11.3 $μ$m PAH feature consistent with the ionized gas rather than the molecular gas. We therefore suggest that PAHs are more closely associated with the ionized gas rather than the molecular at the base of the galaxy outflow, where larger scale imaging shows comparable morphology between PAHs and HI. The 6.2 $μ$m PAH feature has an even higher outflow velocity for both galaxies, possibly suggesting preferential ionization of the PAHs within the faster-moving hot phase of the base of the outflow.
Comments19 pages, 13 figures, Accepted for publication in ApJ
