Interacting galaxies in MOND

Michal Bilek (ObAS)

The purpose of this talk will be to introduce myself and my work so far. Modified Newtonian Dynamics (aka MOND) is the leading alternative to the dark matter hypothesis in galaxies, suggesting a modification of the laws of physics for low accelerations. It can explain various galaxy properties. When applied to the relative orbit of the Milky Way and its nearest big neighbor, the Andromeda Galaxy, it comes out that the galaxies passed close to each other 7-11 Gyr ago. We conducted the first N-body simulation of this encounter. The simulation was set so that the modeled Milky Way and Andromeda eventually roughly reproduced the masses, sizes, disk inclinations, separation, and relative velocity of their real counterparts. The simulated galaxies reached a minimal separation of only 24 kpc. The close encounter induced peculiar features in the simulated galaxies resembling those in the real galaxies. For example, there formed features resembling the Milky Way disk warp, the disk of satellites at the Andromeda Galaxy, or the stellar streams around both of these galaxies. At the end of my talk, I will summarize our work on testing MOND in elliptical galaxies using a special kind of tidal features, the stellar shells, and using the kinematics of their globular cluster systems.