Are Disks of Satellites Comprised of Tidal Dwarf Galaxies?

It was found that satellites of nearby galaxies can form flattened co-rotating structures called disks or planes satellites. Their existence is not expected by the current galaxy formation simulations in standard dark matter-based cosmology. On contrary, modified gravity offers a promising alternative: objects are tidal dwarf galaxies, is, small from tails interacting galaxies. After introducing topic, we review here our work on simulating Milky Way and Andromeda The initial conditions simulation were tuned to reproduce observed positions, velocities disk orientations showed had close flyby 6.8 Gyr ago. One produced captured Andromeda. formed cloud particles resembling at its size, orientation, rotation mass. A hint too. In addition, encounter induced warp simulated resembles real magnitude orientation. We present here, for first time, proper motions members predicted simulation. Finally, point out some remaining open questions which this hypothesis, satellites, brings up.