Abstract / Description of output
Detailed chemical abundances are presented for seven M31 outer halo
globular clusters (with projected distances from M31 greater than 30
kpc), as derived from high-resolution integrated light spectra taken
with the Hobby-Eberly Telescope. Five of these clusters were recently
discovered in the Pan-Andromeda Archaeological Survey (PAndAS) - this
paper presents the first determinations of integrated Fe, Na, Mg, Ca,
Ti, Ni, Ba, and Eu abundances for these clusters. Four of the target
clusters (PA06, PA53, PA54, and PA56) are metal poor ([Fe/H] <-1.5),
α-enhanced (though they are possibly less α-enhanced than
Milky Way stars at the 1σ level), and show signs of star-to-star
Na and Mg variations. The other three globular clusters (H10, H23, and
PA17) are more metal rich, with metallicities ranging from [Fe/H] = -1.4
to -0.9. While H23 is chemically similar to Milky Way field stars, Milky
Way globular clusters, and other M31 clusters, H10 and PA17, have
moderately low [Ca/Fe], compared to Milky Way field stars and clusters.
Additionally, PA17's high [Mg/Ca] and [Ba/Eu] ratios are distinct from
Milky Way stars, and are in better agreement with the stars and clusters
in the Large Magellanic Cloud. None of the clusters studied here can be
conclusively linked to any of the identified streams from PAndAS;
however, based on their locations, kinematics, metallicities, and
detailed abundances, the most metal-rich PAndAS clusters H23 and PA17
may be associated with the progenitor of the Giant Stellar Stream, H10
may be associated with the SW cloud, and PA53 and PA56 may be associated
with the eastern cloud.
Original language | English |
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Pages (from-to) | 1314-1334 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 448 |
Publication status | Published - 1 Apr 2015 |
Keywords / Materials (for Non-textual outputs)
- globular clusters: general
- galaxies: abundances
- galaxies: evolution
- galaxies: individual: M31
- galaxies: star clusters: general