Integrated light chemical tagging analyses of seven M31 outer halo globular clusters from the Pan-Andromeda Archaeological Survey

Charli M. Sakari*, Kim A. Venn, Dougal Mackey, Matthew D. Shetrone, Aaron Dotter, Annette M N Ferguson, Avon Huxor

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

20 Citations (Scopus)

Abstract

Detailed chemical abundances are presented for seven M31 outer halo globular clusters (with projected distances fromM31 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 MilkyWay 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 languageEnglish
Pages (from-to)1314-1337
Number of pages24
JournalMonthly Notices of the Royal Astronomical Society
Volume448
Issue number2
DOIs
Publication statusPublished - 1 Jan 2015

Keywords

  • Galaxies: abundances
  • Galaxies: evolution - galaxies
  • Galaxies: star clusters: general
  • Globular clusters: general
  • Individual: M31

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