Simulations of minor mergers. II. The phase-space structure of thick
  discs
  We analyse the phase-space structure of simulated thick discs that are the
result of a significant merger between a disc galaxy and a satellite. Our main
goal is to establish what would be the characteristic imprints of a merger
origin for the Galactic thick disc. We find that the spatial distribution
predicted for thick disc stars is asymmetric, seemingly in agreement with
recent observations of the Milky Way thick disc. Near the Sun, the accreted
stars are expected to rotate more slowly, to have broad velocity distributions,
and to occupy preferentially the wings of the line-of-sight velocity
distributions. The majority of the stars in our model thick discs have low
eccentricity orbits (in clear reference to the pre-existing heated disc) which
gives rise to a characteristic (sinusoidal) pattern for their line of sight
velocities as function of galactic longitude. The z-component of the angular
momentum of thick disc stars provides a clear discriminant between stars from
the pre-existing disc and those from the satellite, particularly at large
radii. These results are robust against the particular choices of initial
conditions made in our simulations, and thus provide clean tests of the disc
heating via a minor merger scenario for the formation of thick discs.
