Bibcode
DOI
Williams, Benjamin F.; Ciardullo, Robin; Durrell, Patrick R.; Feldmeier, John J.; Sigurdsson, Steinn; Vinciguerra, Matt; Jacoby, George H.; von Hippel, Ted; Ferguson, Henry C.; Tanvir, Nial R.; Arnaboldi, Magda; Gerhard, Ortwin; Aguerri, J. Alfonso L.; Freeman, Ken C.
Referencia bibliográfica
The Astrophysical Journal, Volume 654, Issue 2, pp. 835-843.
Fecha de publicación:
1
2007
Revista
Número de citas
45
Número de citas referidas
40
Descripción
We report the discovery of four candidate intracluster globular clusters
(IGCs) in a single deep HST ACS field of the Virgo Cluster. We show that
each cluster is roughly spherical, has a magnitude near the peak of the
Virgo globular cluster luminosity function, has a radial profile that is
best fitted by a King model, and is surrounded by an excess of point
sources that have the colors and magnitudes of cluster red giant stars.
Despite the fact that two of our IGC candidates have integrated colors
redder than the mean of the M87 globular cluster system, we propose that
all of the objects are metal-poor, with [M/H]<-1. We show that the
tidal radii of our intracluster globular clusters are all larger than
the mean for Milky Way clusters and suggest that the clusters have
undergone less tidal stress than their Galactic counterparts. Finally,
we normalize our globular cluster observations to the luminosity of
intracluster stars and derive a value of SN~6 for the
specific frequency of Virgo intracluster globular clusters. We use these
data to constrain the origins of Virgo's intracluster population and
suggest that globular clusters in our intracluster field have a
different origin than globular clusters in the vicinity of M87. In
particular, we argue that dwarf elliptical galaxies may be an important
source of intracluster stars.