The GOTHAM survey: chemical evolution of Milky Way globular clusters

Date Issued
2018
Author(s)
Dias, Bruno
•
Barbuy, Beatriz
•
Saviane, Ivo
•
•
da Costa, Gary
•
•
DOI
Abstract
Milky Way globular clusters are excellent laboratories for stellar population detailed analysis that can be applied to extragalactic environments with the advent of the 40m-class telescopes like the ELT. The globular cluster population traces the early evolution of the Milky Way which is the field of Galactic archaeology. We present our GlObular clusTer Homogeneous Abundance Measurement (GOTHAM) survey. We derived radial velocities, Teff, log(g), [Fe/H], [Mg/Fe] for red giant stars in one third of all Galactic globular clusters that represent well the Milky Way globular cluster system in terms of metallicity, mass, reddening, and distance. Our method is based on low-resolution spectroscopy and is intrinsically reddening free and efficient even for faint stars. Our [Fe/H] determinations agree with high-resolution results to within 0.08 dex. The GOTHAM survey provides a new metallicity scale for Galactic globular clusters with a significant update of metallicities higher than [Fe/H] > -0.7. We show that the trend of [Mg/Fe] with metallicity is not constant as previously found, because now we have more metal-rich clusters. Moreover, peculiar clusters whose [Mg/Fe] does not match Galactic stars for a given metallicity are discussed. We also measured the CaII triplet index for all stars and we show that the different chemical evolution of Milky Way open clusters, field stars, and globular clusters implies different calibrations of calcium triplet to metallicity.
Coverage
Rediscovering Our Galaxy
All editors
Chiappini, C.; Minchev, I.; Starkenburg, E.; Valentini, M.
Series
Volume
vol. 13, S334
Start page
25
Conferenece
Rediscovering our Galaxy
Conferenece place
Potsdam, Germany
Conferenece date
10-14 July, 2017
Uri
Url
Issn Identifier
1743-9213
Ads BibCode
2018IAUS..334...25D
Rights
open.access
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