De la conception instrumentale
à l’exploitation des observables

Soutenance de thèse de Yan Qu

Angular momentum evolution and the impact of minor mergers on disk galaxies
» vendredi 19 novembre 2010

Advisor :

  • Matthew Lehnert (GEPI, Observatoire de Paris)

Galactic stellar disks account for only a small portion of the total
baryonic mass of the local volume, but they dominate the angular momentum
budget of the Universe. The formation and evolution of galactic disks
are intertwined with the development of angular momentum with cosmic
time. Although a detailed picture of the angular momentum evolution of
the baryons in a hierarchical universe is still lacking, it is clear that
merging of galaxies is one of the fundamental drivers of galaxy evolution
with perhaps an especially important role for mergers with large mass
ratios — minor mergers. In order to gain more insight in the physical
processes that determine the evolution of angular momentum in galaxies
we explore, through the use of N- body/Smooth Particle Hydrodynamical
numerical simulations, the angular momentum redistribution during a
large number of minor galaxy mergers and investigate their impact on
the dynamical and morphological properties of disks. Overall, this
thesis study demonstrates the fundamental role angular momentum plays
during galaxy minor merger processes in altering stellar disk properties
and driving galaxy evolution, and indicates that minor mergers may be
a viable mechanism to explain many of the observed properties of disk galaxies
in the local Universe.

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