Dr Kenji Bekki (University of New South Wales)

The mysterious age gap of globular clusters in the Large Magellanic Cloud - Dr Kenji Bekki Colloquium

ATNF Marsfield Lecture Theatre

Abstract

The Large Magellanic Cloud (LMC) has a unique cluster formation history
in that nearly all of its globular clusters were formed either ~ 13
Gyr ago or less than ~ 3 Gyr ago.
It is not clear what physical mechanism is responsible for the most
recent cluster formation episode and thus the mysterious age gap
between the LMC clusters.
We first present results of gas dynamical
N-body simulations
of the evolution of the LMC in the context of its Galactic orbit
and interactions with the SMC, paying special attention to the effect
of tidal forces.
We find that
the first close encounter
between the LMC and the Small Magellanic Cloud (SMC) about 4 Gyr ago
was the beginning of a period of strong tidal interaction which
likely induced dramatic gas cloud collisions, leading to an enhancement
of the formation of globular clusters which has been sustained by
strong tidal interactions to the present day.
The tidal interaction results in the formation of a barred, elliptical,
thick disk in the LMC.
The model also predicts the presence
of a large, diffuse stellar stream circling the Galaxy, which originated
from the LMC.