R. Salinas, L. Jílková, G. Carraro, M. Catelan, P. Amigo
We present BV photometry of four Sagittarius dwarf spheroidal galaxy globular
clusters: Arp 2, NGC 5634, Palomar 12, and Terzan 8, obtained with the Danish
telescope at ESO-La Silla. We measure the structural parameters of the clusters
using a King profile fitting, obtaining the first reliable measurements of the
tidal radius of Arp 2 and Terzan 8. These two clusters are remarkably extended
and with low concentrations; with a concentration of only c = 0.41 +/- 0.02,
Terzan 8 is less concentrated than any cluster in our Galaxy. Blue stragglers
are identified in the four clusters, and their spatial distribution is compared
to those of horizontal branch and red giant branch stars. The blue straggler
properties do not provide evidence of mass segregation in Terzan 8, while Arp 2
probably shares the same status, although with less confidence. In the case of
NGC 5634 and Palomar 12, blue stragglers are significantly less populous, and
their analysis suggests that the two clusters have probably undergone mass
segregation.
View original:
http://arxiv.org/abs/1112.1614
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