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Paper: The AGB Population of NGC 6822
Volume: 445, Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants
Page: 409
Authors: Sibbons, L. F.; Cioni, M.-R. L.; Irwin, M.; Rejkuba, M.
Abstract: The metallicity gradient and the stellar distribution within the Local Group dwarf galaxy NGC 6822 has been studied photometrically using asymptotic branch (AGB) stars. In order to study the stellar and metallicity distributions, the carbon- and oxygen-rich AGB stars have been isolated using deep high-quality near-infrared UKIRT photometry. The ratio between them, the C/M ratio, has been used to derive the [Fe/H] abundance within the galaxy. The [Fe/H] abundance and stellar distribution were analysed as a function of galactic radius. A mean C/M ratio of 0.288±0.014 has been found, which corresponds to an iron abundance of [Fe/H] = –1.14±0.08 dex, with variations in the north and south as well as at larger galactocentric distances. Variations in the magnitude of the tip of the red giant branch have also been detected.
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