A Detailed GASKAP-HI View of Shells and Loops in the Magellanic Bridge
Abstract
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.
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BibTeX
@misc{kim2026detailed,
title = {{A Detailed GASKAP-HI 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},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.18160},
eprint = {2609.18160},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.18160},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Detailed GASKAP-HI 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 - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.18160
UR - https://arxiv.org/abs/2609.18160
AB - 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.
ER -