Effects of ram pressure on the gas distribution and star formation in the Large Magellanic Cloud

TL;DR

This study uses high-resolution simulations to explore how ram pressure from the Milky Way's hot halo influences the gas distribution and star formation in the Large Magellanic Cloud, explaining observed features.

Contribution

It demonstrates that ram-pressure effects can account for the HI distribution peculiarities and star formation patterns in the LMC, considering different disk orientations.

Findings

High-density HI regions at the southeast border due to compression.

Clumpy HI structures resembling observations from the Parkes survey.

Young stellar complexes show age progression along the leading edge.

Abstract

We use high resolution N-body/SPH simulations to study the hydrodynamical interaction between the Large Magellanic Cloud (LMC) and the hot halo of the Milky Way. We investigate whether ram-pressure acting on the satellite's ISM can explain the peculiarities observed in the HI distribution and the location of the recent star formation activity. Due to the present nearly edge-on orientation of the disk with respect to the orbital motion, compression at the leading edge can explain the high density region observed in HI at the south-east border. In the case of a face-on disk (according to Mastropietro et al. 2008 the LMC was moving almost face-on before the last perigalactic passage), ram-pressure directed perpendicularly to the disk produces a clumpy structure characterized by voids and high density filaments that resemble those observed by the Parkes HI survey. As a consequence of the very recent edge-on motion, the H-alpha emission is mainly concentrated on the eastern side where 30 Doradus and most of the supergiant shells are located, although some H-alpha complexes form a patchy distribution on the entire disk. In this scenario only the youngest stellar complexes show a progression in age along the leading border of the disk.