30,129 research outputs found
The Star Cluster Systems of the Magellanic Clouds
The characteristics of the cluster systems of the Magellanic Clouds, as
inferred from integrated properties, are compared with those from individual
cluster studies and from the field population. The agreement is generally
satisfactory though in the case of the LMC, the lack of clusters older than ~3
Gyr is not reflected in the field population. The possible origin(s) for this
cluster ``age-gap'' are discussed. The SMC cluster age-metallicity relation is
also presented and discussed.Comment: 11 pages, 4 figures. To appear in the Proceedings of IAU Symposium
207, "Extragalactic Star Clusters", eds E. Grebel, D. Geisler and D. Minnit
A Second Shell in the Fornax dSph Galaxy
In the search for tidal structure in Galactic satellite systems, we have
conducted a photometric survey over a 10 square degree area centred on the
Fornax dSph galaxy. The survey was made in two colours, and the resulting
colour-magnitude data were used as a mask to select candidate Fornax RGB stars,
thereby increasing the contrast of Fornax stars to background sources in the
outer regions. Previously, we reported the presence of a shell (age 2 Gyr)
located towards the centre of Fornax. In this contribution we reveal a second
shell, significantly larger than the first, located 1.3 degrees NW from the
centre of Fornax, outside the nominal tidal radius. Moreover, the distribution
of Fornax RGB stars reveals two lobes extending to the spatial limit of our
survey, and aligned with the minor axis and with the two shells. These results
support the hypothesis of a merger between Fornax and a gas-rich companion
approximately 2 Gyr ago.Comment: Four pages,accepted for the Publications of the Astronomical Society
of Australia. Contribution the annual ASA meeting, Brisbane 200
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