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

We use high-resolution N-body/smoothed particle hydrodynamics (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 interstellar medium 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 disc 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 disc (according to Mastropietro the LMC was moving almost face-on before the last perigalactic passage), ram pressure directed perpendicular to the disc 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 disc. In this scenario, only the youngest stellar complexes show a progression in age along the leading border of the disc.