Stellar density distribution along the minor axis of the Large Magellanic Cloud

TL;DR

This study maps the distribution of young and old stars along the western minor axis of the Large Magellanic Cloud, revealing differences in density and shape that inform its interaction history with the Milky Way.

Contribution

It provides new detailed measurements of stellar populations' spatial distribution in the LMC, highlighting differences in elongation and density that challenge recent tidal interaction hypotheses.

Findings

Old populations are three times denser than young populations at the LMC limit.

Old populations are more elongated than young populations.

Presence of young stars in outer regions suggests ram pressure stripping effects.

Abstract

We studied the spatial distribution of young and old stellar populations along the western half part of the minor axis of the Large Magellanic Cloud (LMC) using Washington MT1 photometry of selected fields, which span a deprojected distance range from the LMC bar centre out to ~ 31.6 kpc. We found that both stellar populations share a mean LMC limiting radius of 8.9+-0.4 kpc; old populations are three times more dense that young populations at that LMC limit. When comparing this result with recent values for the LMC extension due to north, the old populations resulted significantly more elongated than the young ones. Bearing in mind previous claims that the elongation of the outermost LMC regions may be due to the tidal effects of the Milky Way (MW), our findings suggest that such a tidal interaction should not have taken place recently. The existence of young populations in the outermost western regions also supports previous results about ram pressure stripping effects of the LMC gaseous disc due to the motion of the LMC in the MW halo.