麦哲伦桥中壳层与环的详细GASKAP-HI观测
A Detailed GASKAP-HI View of Shells and Loops in the Magellanic Bridge
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中文总结 AI 辅助
本研究利用GASKAP-HI观测麦哲伦桥中与DEM171相关的HI壳层，通过高斯分解和傅里叶变换揭示冷气体多相结构，发现恒星反馈促进冷气体形成，并展示冷HI气体在广泛空间尺度上的存在。
中文摘要 AI 辅助
我们展示了与麦哲伦桥中Hα壳层DEM171相关联的HI壳层（直径约130秒差距）的8秒差距尺度GASKAP-HI观测结果。麦哲伦桥弥散、以HI为主的环境，具有极小的星系剪切效应和较少重叠的恒星形成区域，为研究由恒星反馈驱动的冷气体形成提供了理想环境。为了研究该壳层的HI多相结构和运动学，我们对HI谱线轮廓进行了高斯分解。我们在壳层内识别出速度弥散σ<2.5 km/s的冷HI成分。互补的赫歇尔远红外（FIR）250微米和Hα图像显示，虽然中心空腔被电离，但壳层壁包含冷HI、分子气体和尘埃，这表明恒星反馈促进了冷气体的形成，或将先前存在的冷气体扫入壳层壁。我们还在壳层外部识别出追踪更大尺度结构MB-Loop I的冷HI团块。为了研究大尺度背景，我们将傅里叶变换方法应用于HI发射线轮廓，以绘制麦哲伦桥一段区域内冷气体柱密度的下限，揭示从大环到较小壳层的结构。MB-Loop I与HI壳层之间的关联表明，冷HI气体可能在壳层膨胀之前就已存在。最后，该壳层表现出不对称膨胀，其优选方向大致垂直于沿MB-Loop I的弧。我们的结果表明，冷HI气体存在于麦哲伦桥中广泛的空间尺度上，突显了塑造周围星际介质的动态相互作用。
英文摘要
We present 8 pc-scale GASKAP-HI observations of an HI shell (diameter \sim130 pc) associated with the Hαshell DEM171 in the Magellanic Bridge. The Bridge's diffuse, HI-dominated environment, with minimal galactic shearing and fewer overlapping star-forming regions, provides an ideal environment to study cold gas formation driven by stellar feedback. To investigate the HI multi-phase structure and kinematics of the shell, we perform Gaussian decomposition of HI line profiles. We identify cold HI components with velocity dispersions σ< 2.5 km/s located within the shell. Complementary Herschel far-infrared (FIR) 250\micron and Hαmaps show that while the central cavity is ionized, the shell walls contain cold HI, molecular gas, and dust, suggesting that stellar feedback has promoted cold gas formation or swept pre-existing cold gas into the shell walls. We also identify cold HI clumps outside the shell tracing a larger-scale structure, MB-Loop I. To investigate the large-scale context, we apply a Fourier transform method to HI emission-line profiles to map the lower limit of cold-gas column densities across a section of the Bridge, revealing structures from large loops to smaller shells. The association between MB-Loop I and the HI shell suggests that cold HI gas may pre-exist before shell expansion. Finally, the shell exhibits asymmetric expansion, with a preferred orientation roughly perpendicular to the arc along MB-Loop I. Our results show that cold HI gas exists across a wide range of spatial scales in the Magellanic Bridge, highlighting the dynamic interplay that shapes the surrounding interstellar medium.
发表机构
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Observatoire de Paris（巴黎高等师范学院物理实验室，巴黎文理研究大学，法国国家科学研究中心，索邦大学，巴黎西岱大学，巴黎天文台）
- SKA Observatory, Jodrell Bank（平方公里阵列射电望远镜天文台，乔德雷尔银行）
- School of Mathematical and Physical Sciences and Astrophysics and Space Technologies Research Centre, Macquarie University（麦考瑞大学数理科学与天体物理及太空技术研究学院）
- College of Sciences and Engineering, Universidad San Francisco de Quito（基多圣弗朗西斯科科技大学科学与工程学院）
- School of Natural Sciences, University of Tasmania（塔斯马尼亚大学自然科学学院）
- Department of Physics and Astronomy, Western Kentucky University（肯塔基西部大学物理与天文系）
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