Action space analysis. Top: X–Z projection of in situ stars (left), all accreted stars (middle), and surviving satellites (right) in 09–18 M31 galaxy at z = 0. The density maps and the action space analysis are based on the stars (accreted and in situ) > 1 kpc from the galactic plane. Different survived satellites are shown in different colours. Second row: J_z − J_r plane for in situ (left), the fraction of accreted stellar mass (centre), and surviving satellites (right). Third row: (J_r − J_z)/J_tot − J_ϕ/J_tot plane for in situ (left), faction of accreted stellar mass (centre), and survived satellites (right). Bottom row: plane for in situ (left), faction of accreted stellar mass (center), and survived satellites (right). While in situ and accreted stars do not show any prominent features in the action space, the dwarf satellites, as expected, are seen as coherent structures. Accreted stars have on average larger radial and vertical actions, but still substantially overlap with the in situ populations at smaller values.