A detailed GASKAP-H i view of shells and loops in the Magellanic Bridge
Abstract
We present 8-pc-scale Galactic Australian Square Kilometre Array Pathfinder-H i observations of an H i shell (diameter ∼130 pc) associated with the H α shell DEM171 in the Magellanic Bridge. The Bridge's diffuse, H i -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 H i multiphase structure and kinematics of the shell, we perform Gaussian decomposition of H i line profiles. We identify cold H i components with velocity dispersions σ < 2 . 5 km s -1 located within the shell. Complementary Herschel far-infrared 250 µm and H α maps show that while the central cavity is ionized, the shell walls contain cold H i , 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 H i 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 H i 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 H i shell suggests that cold H i 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 H i gas exists across a wide range of spatial scales in the Magellanic Bridge, highlighting the dynamic interplay that shapes the surrounding interstellar medium.
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BibTeX
@article{kim2026detailed,
title = {{A detailed GASKAP-H i view of shells and loops in the Magellanic Bridge}},
author = {Shin-Jeong Kim and Antoine Marchal and N M Mcclure-Griffiths and J R Dawson and James Dempsey and Helga Dénes and John M Dickey and Steven J Gibson and Katie Jameson and Ian Kemp and Bumhyun Lee and Min-Young Lee and Adam K Leroy and Callum Lynn and Yik Ki Ma and Marc-Antoine Miville-Deschênes and Eric G M Muller and Claire Murray and Hiep Nguyen and Nickolas Pingel and Hye-Jin Park and Jacco Th van Loon},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = sep,
doi = {10.1093/mnras/stag1763},
url = {https://hal.science/hal-05848984v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A detailed GASKAP-H i view of shells and loops in the Magellanic Bridge
AU - Shin-Jeong Kim
AU - Antoine Marchal
AU - N M Mcclure-Griffiths
AU - J R Dawson
AU - James Dempsey
AU - Helga Dénes
AU - John M Dickey
AU - Steven J Gibson
AU - Katie Jameson
AU - Ian Kemp
AU - Bumhyun Lee
AU - Min-Young Lee
AU - Adam K Leroy
AU - Callum Lynn
AU - Yik Ki Ma
AU - Marc-Antoine Miville-Deschênes
AU - Eric G M Muller
AU - Claire Murray
AU - Hiep Nguyen
AU - Nickolas Pingel
AU - Hye-Jin Park
AU - Jacco Th van Loon
PY - 2026
DA - 2026/09/24
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/stag1763
UR - https://hal.science/hal-05848984v1
AB - We present 8-pc-scale Galactic Australian Square Kilometre Array Pathfinder-H i observations of an H i shell (diameter ∼130 pc) associated with the H α shell DEM171 in the Magellanic Bridge. The Bridge's diffuse, H i -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 H i multiphase structure and kinematics of the shell, we perform Gaussian decomposition of H i line profiles. We identify cold H i components with velocity dispersions σ < 2 . 5 km s -1 located within the shell. Complementary Herschel far-infrared 250 µm and H α maps show that while the central cavity is ionized, the shell walls contain cold H i , 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 H i 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 H i 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 H i shell suggests that cold H i 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 H i gas exists across a wide range of spatial scales in the Magellanic Bridge, highlighting the dynamic interplay that shapes the surrounding interstellar medium.
SN - 0035-8711
SN - 1365-2966
ER -