Le 9 décembre 2016
De 10h30 à 12h00
Chervin LAPORTE
Columbia University
The Milky Way disc is asymmetric about the midplane. The HI shows a warp, and recent star count surveys show that the disc is rippled (both in height and streaming vertical velocity): their respective origins are still not settled. I will show results that suggest that all these features in the MW disc are shaped by its two most massive satellites. I will present the first self-consistent N-body models of the MW and LMC pair in a first infall scenario designed to study the response of the disc to different mass models. I will show that a massive LMC of virial mass 2.5×10^11 Msun predicts a warp with the correct phases as the observed HI warp but no ripples. However, discrepancies remain between the models and the data, and I will discuss some possible reasons. By contrasting the response of the disc with a heavy Sgr model I will also show that no single interaction model (MW+LMC/MW+Sgr) can capture all the features seen in the disc, and that one should consider the collective effect of both satellites. I will then present some revised models of Sgr interacting with the MW that I am now using to study the coupling between the LMC and Sgr on the Galactic disc (Laporte et al. in prep).