The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge

Howes, LM; Asplund M.; Casey, AR; Keller, SC; Yong D.; Gilmore, G; Lind, K; Worley, C.; Bessell, MS; Casagrande, L; Marino, AF; Nataf, DM; Owen, CI; Da Costa, GS; Schmidt, BP; et. al.

Keywords: stars: population ii, stars: abundances, galaxy: bulge, galaxy: evolution

Abstract

We present the first results of the EMBLA survey (Extremely Metal-poor BuLge stars with AAOmega), aimed at finding metal-poor stars in the Milky Way bulge, where the oldest stars should now preferentially reside. EMBLA utilizes SkyMapper photometry to pre-select metal-poor candidates, which are subsequently confirmed using AAOmega spectroscopy. We describe the discovery and analysis of four bulge giants with -2.72 <= [Fe/H] <= -2.48, the lowest metallicity bulge stars studied with high-resolution spectroscopy to date. Using FLAMES/UVES spectra through the Gaia-ESO Survey we have derived abundances of twelve elements. Given the uncertainties, we find a chemical similarity between these bulge stars and halo stars of the same metallicity, although the abundance scatter may be larger, with some of the stars showing unusual [alpha/Fe] ratios.

Más información

Título según WOS: The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge
Título según SCOPUS: The Gaia-ESO Survey: The most metal-poor stars in the Galactic bulge
Título de la Revista: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volumen: 445
Número: 4
Editorial: Oxford Academic
Fecha de publicación: 2014
Página de inicio: 4241
Página final: 4246
Idioma: English
DOI:

10.1093/mnras/stu1991

Notas: ISI, SCOPUS