A Recent Major Merger Tale for the Closest Giant Elliptical Galaxy
  Centaurus A
  We have used hydrodynamical simulations to model the formation of the closest
giant elliptical galaxy, Centaurus A. We find that a single major merger event
with a mass ratio up to 1.5, and which has happened ~2 Gyr ago, is able to
reproduce many of its properties, including galaxy kinematics, the inner gas
disk, stellar halo ages and metallicities, and numerous faint features observed
in the halo. The elongated halo shape is mostly made of progenitor residuals
deposited by the merger, which also contribute to stellar shells observed in
the Centaurus A halo. The current model also reproduces the measured Planetary
Nebulae line of sight velocity and their velocity dispersion. Models with small
mass ratio and relatively low gas fraction result in a de Vaucouleurs profile
distribution, which is consistent with observations and model expectations. A
recent merger left imprints in the age distribution that are consistent with
the young stellar and Globular Cluster populations (2-4 Gyrs) found within the
halo. We conclude that even if not all properties of Centaurus A have been
accurately reproduced, a recent major merger has likely occurred to form the
Centaurus A galaxy as we observe it at present day.
