[SEMINARI] Extragalactic Globular Clusters populations as probes of the evolution of the host galaxy

[Enric Marco]

Extragalactic Globular Clusters populations as probes of the evolution
of the host galaxy 

Paolo Bonfini, Universidad de Creta.

Fecha: viernes 27 Abril 2012
Hora: 11:30
Lugar: Sala seminarios del OAUV

Abstract: 
Globular Clusters (GCs) are compact groups of stars containing 10^4 to
10^6 objects. 
To a first approximation, they can be considered as isolated systems
of old stars. Therefore, they 
reflect the metallicity of the host galaxy at the moment of their
creation. In particular, is 
interesting to notice that GC populations of almost all Elliptical
galaxies show a clear colour 
bimodality (explained by a metallicity difference), which addresses to
different formation/evolution 
paths as related to the host galaxy's history. 
Moreover, due to their brightness, extragalactic GCs usually stand out
very clearly over the host 
galaxy background, and they can be used as tracers of the galaxy's
dynamics well beyond the limit 
where the galaxy surface brightness fades below the background signal. 
For these reasons, GCs can be considered excellent labs to explore the
host galaxy's evolution. 

We recently investigated the case of the elliptical galaxy NGC 4261,
which exhibits a peculiar 
asymmetric two-dimensional distribution of its GC population - despite
its overall uniform starlight - 
and suggested that the origin of the asymmetry could be related to a
past (dry) merger or interaction 
event (e.g. fly-by encounter).