The Origin of Large-scale HI structures in the Magellanic Bridge

TL;DR

This study uses numerical simulations to explore the formation of large-scale HI structures in the Magellanic Bridge, revealing tidal filaments and bimodal configurations without needing energetic local processes.

Contribution

It provides the first direct comparison between detailed HI observations and numerical models, demonstrating tidal origins of key structures in the Magellanic Bridge.

Findings

Confirmation of two tidal filaments from the SMC: a near arm and a counterarm.

Reproduction of a HI 'loop' as a projection of the counter-arm without local energy input.

Dense HI regions can form bimodal configurations due to tidal interactions.

Abstract

We investigate the formation of a number of key large-scale HI features in the ISM of the Magellanic Bridge using dissipationless numerical simulation techniques. This study comprises the first direct comparison between detailed HI maps of the Bridge and numerical simulations. We confirm that the SMC forms two tidal filaments: a near arm, which forms the connection between the SMC and LMC, and a counterarm. We show that the HI of the most dense part of the Bridge can become arranged into a bimodal configuration, and that the formation of a "loop" of HI, located off the North-Eastern edge of the SMC can be reproduced simply as a projection of the counter-arm, and without invoking localised energy-deposition processes such as SNe or stellar winds.