Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code – II. The Southern clusters and overview
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Fecha
2020-02
Profesor/a Guía
Facultad/escuela
Idioma
en
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Editor
Oxford University Press
Nombre de Curso
Licencia CC
Licencia CC
Resumen
We investigate the Fe, C, N, O, Mg, Al, Si, K, Ca, Ce, and Nd abundances of 2283 red giant
stars in 31 globular clusters from high-resolution spectra observed in both the Northern and
Southern hemisphere by the SDSS-IV APOGEE-2 survey. This unprecedented homogeneous
data set, largest to date, allows us to discuss the intrinsic Fe spread, the shape, and statistics of
Al-Mg and N-C anti-correlations as a function of cluster mass, luminosity, age, and metallicity
for all 31 clusters. We find that the Fe spread does not depend on these parameters within
our uncertainties including cluster metallicity, contradicting earlier observations. We do not
confirm the metallicity variations previously observed in M22 and NGC 1851. Some clusters
show a bimodal Al distribution, while others exhibit a continuous distribution as has been
previously reported in the literature. We confirm more than two populations in ω Cen and
NGC 6752, and find new ones in M79. We discuss the scatter of Al by implementing a
correction to the standard chemical evolution of Al in the Milky Way. After correction, its
dependence on cluster mass is increased suggesting that the extent of Al enrichment as a
function of mass was suppressed before the correction. We observe a turnover in the Mg-Al
anticorrelation at very low Mg in ω Cen, similar to the pattern previously reported in M15 and
M92. ω Cen may also have a weak K-Mg anticorrelation, and if confirmed, it would be only
the third cluster known to show such a pattern
Notas
Palabras clave
astronomical data bases: miscellaneous – surveys – stars, galaxies: abundances – stars: late-type – globular clusters: general – galaxies: fundamental parameters.
Citación
Monthly Notices of the Royal Astronomical Society Open AccessVolume 492, Issue 2, Pages 1641 - 16701 February 2020