Projection of a stellar stream from our simulations in its progenitor’s orbital plane at t = 3 Gyr, for the reference run (top) and the merger run (bottom). The Milky Way’s centre of mass is at (x, y) = (0,0) and the progenitor is located at x = 0. The solid curves are the 1-DREAM fits to the stream (blue for the reference case, red for the merger case). The panels below each map display the corresponding density profiles along the stream.