The gravitational and hydrodynamical interaction between the LMC and the Galaxy

Abstract

We use high resolution N-Body/SPH simulations to study the hydrodynamical and gravitational interaction between the Large Magellanic Cloud and the Milky Way. We model the dark and hot extended halo components as well as the stellar/gaseous disks of the two galaxies. Both galaxies are embedded in extended cuspy LCDM dark matter halos. We follow the previous four Gyrs of the LMC's orbit such that it ends up with the correct location and orientation on the sky. Tidal forces elongate the LMC's disk, forcing a bar and creating a strong warp and diffuse stellar halo, although very few stars become unbound. The stellar halo may account for some of the microlensing events. Ram-pressure from a low density ionised halo is then sufficient to remove 1.4e8 Msolar of gas from the LMC's disk forming a great circle trailing stream around the Galaxy. The column density of stripped gas falls by two orders of magnitude 100 degrees from LMC. The LMC does not induce any response in the Milky Way disk. On the contrary, the tides raised by the Milky Way determine the truncation of the satellite at about 11 kpc. After several Gyrs of interaction the gas disk of the LMC is smaller than the stellar disk due to ram pressure and its size compares well with the observational data.