The top panel gives the distribution of z component of the angular momentum of stellar particles for model M3L34. The galaxy has been projected edge-on using the angular momentum of the baryons. From left to right, star of different age (from young, intermediate, and old) are shown. Old stars (red dots) already exist in the progenitors at the beginning of the simulation. Young stars (blue dots) are defined with ages over 3 Gyr after the beginning of the simulation. Ages between young and old are defined as intermediate stars (green dots), which are formed before the fusion. The bottom panel shows the projected mass distribution of the thin disc (left), and the bulge and thick disc (right). The thin disc is selected from its angular momentum ratio (MAz/MA  ≥  0.9, see Hammer et al. 2010), which cuts the warp off. Each panel has a size of 300 by 300 kpc.