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The SLUGGS survey: calcium triplet-based spectroscopic metallicites for over 900 globular clusters
Monthly Notices of the Royal Astronomical Society (2012)
  • C. Usher, Swinburne University of Technology
  • D. A. Forbes, Swinburne University of Technology
  • J. P. Brodie
  • C. Foster
  • L. R. Spitler, Swinburne University of Technology
  • J. A. Arnold
  • Aaron J. Romanowsky, San Jose State University
  • J. Strader
  • V. Pota, Swinburne University of Technology
Abstract

Although the colour distribution of globular clusters in massive galaxies is well known to be bimodal, the spectroscopic metallicity distribution has been measured in only a few galaxies. After redefining the calcium triplet index–metallicity relation, we use our relation to derive the metallicity of 903 globular clusters in 11 early-type galaxies. This is the largest sample of spectroscopic globular cluster metallicities yet assembled. We compare these metallicities with those derived from Lick indices finding good agreement. In six of the eight galaxies with sufficient numbers of high-quality spectra we find bimodality in the spectroscopic metallicity distribution. Our results imply that most massive early-type galaxies have bimodal metallicity as well as colour distributions. This bimodality suggests that most massive early-type galaxies experienced two periods of star formation.

Publication Date
2012
Publisher Statement
Copyright © 2013 Oxford University Press. The published article may be found at :http://dx.doi.org/10.1111/j.1365-2966.2012.21801.x.
Citation Information
C. Usher, D. A. Forbes, J. P. Brodie, C. Foster, et al.. "The SLUGGS survey: calcium triplet-based spectroscopic metallicites for over 900 globular clusters" Monthly Notices of the Royal Astronomical Society Vol. 426 Iss. 2 (2012)
Available at: http://works.bepress.com/aaron_romanowsky/22/