Bibcode
Sikkema, G.; Peletier, R. F.; Carter, D.; Valentijn, E. A.; Balcells, M.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 458, Issue 1, October IV 2006, pp.53-67
Fecha de publicación:
10
2006
Revista
Número de citas
29
Número de citas referidas
28
Descripción
Context: .Shells in Elliptical Galaxies are faint, sharp-edged features,
believed to provide evidence of a recent (˜ 0.5 - 2 ×
109 years ago) merger event. We analyse the Globular Cluster
(GC) systems of six shell elliptical galaxies, to examine the effects of
mergers upon the GC formation history. Aims: .We examine the
colour distributions, and investigate differences between red and blue
globular cluster populations. We present luminosity functions, spatial
distributions and specific frequencies (S N) at 50 kpc radius
for our sample. Methods: .We present V and I magnitudes for
cluster candidates measured with the HST Advanced Camera for Surveys
(ACS). Galaxy background light is modelled and removed, and magnitudes
are measured in 8 pixel (0.4 arcsec) diameter apertures. Background
contamination is removed using counts from Hubble Deep Field South. Results: . We find that the colour distributions for NGC 3923 and NGC
5982 have a bimodal form typical of bright ellipticals, with peaks near
V-I=0.92 ± 0.04 and V-I=1.18 ± 0.06. In NGC 7626, we find
in addition a population of abnormally luminous clusters at M_I=-12.5.
In NGC 2865 we find an unusually blue population, which may also be
young. In NGC 1344 and NGC 474 the red cluster population is marginally
detected. The radial surface density profiles are more flattened than
the galaxy light in the cores. As already known, in NGC 3923, which has
a high S N of 5.6, the radial density distribution is more
shallower than the diffuse galaxy light. Conclusions: .The
clusters in NGC 2865 and NGC 7626 provide evidence for formation of a
population associated with a recent merger. In the other galaxies, the
properties of the clusters are similar to those observed in other,
non-shell, elliptical galaxies.