The detection of an older population in the Magellanic Bridge

TL;DR

This paper investigates the stellar content of the Magellanic Bridge using infrared data, revealing an older stellar population alongside the known younger stars, suggesting complex formation history involving tidal interactions.

Contribution

It provides the first evidence of an older stellar population in the Magellanic Bridge, enhancing understanding of its formation and stellar composition.

Findings

Detection of candidate older stars in the Bridge

Evidence supporting a tidal formation scenario

Analysis of foreground removal techniques

Abstract

The Magellanic system comprises the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC), and the less frequently observed Magellanic Bridge and Magellanic Stream. The Bridge is traced by neutral gas and has an observed stellar component, while the Stream consists of gas only, with no observed stellar counterpart to date. This study uses catalogues created in the direction of the Bridge from 2MASS and WISE to investigate the stellar content of the Magellanic Bridge. Catalogues were created and colour-magnitude and two colour diagrams were analysed. A study was also carried out on removing the Galactic foreground population in the direction of the Magellanic Bridge, which was an important consideration due to the low stellar density within the Bridge. This study finds that the Magellanic Bridge contains a candidate older stellar population in addition to the younger population already known. The formation of the Magellanic Bridge is likely to have occurred from a tidal event between the LMC and SMC drawing most of the material into it from the SMC. An older population in the Bridge indicates that a stellar content was drawn in during its formation together with a gas component.