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 [a/Fe] ratios.
The Gaia-ESO Survey: The most metal-poor stars in the Galactic bulge / Howes L.M.; Asplund M.; Casey A.R.; Keller S.C.; Yong D.; Gilmore G.; Lind K.; Worley C.; Bessell M.S.; Casagrande L.; Marino A.F.; Nataf D.M.; Owen C.I.; Da Costa G.S.; Schmidt B.P.; Tisserand P.; Randich S.; Feltzing S.; Vallenari A.; Allende Prieto C.; Bensby T.; Flaccomio E.; Korn A.J.; Pancino E.; Recio-Blanco A.; Smiljanic R.; Bergemann M.; Costado M.T.; Damiani F.; Heiter U.; Hill V.; Hourihane A.; Jofre P.; Lardo C.; de Laverny P.; Magrini L.; Maiorca E.; Masseron T.; Morbidelli L.; Sacco G.G.; Minniti D.; Zoccali M.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - STAMPA. - 445:4(2014), pp. 4241-4246. [10.1093/mnras/stu1991]
The Gaia-ESO Survey: The most metal-poor stars in the Galactic bulge
Lardo C.;
2014
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 [a/Fe] ratios.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
