Looking for imprints of the first stellar generations in metal-poor
  bulge field stars
  Context. Efforts to look for signatures of the first stars have concentrated
on metal-poor halo objects. However, the low end of the bulge metallicity
distribution has been shown to host some of the oldest objects in the Milky Way
and hence this Galactic component potentially offers interesting targets to
look at imprints of the first stellar generations. As a pilot project, we
selected bulge field stars already identified in the ARGOS survey as having
[Fe/H] ~ -1 and oversolar [alpha/Fe] ratios, and we used FLAMES-UVES to obtain
detailed abundances of key elements that are believed to reveal imprints of the
first stellar generations. Aims. The main purpose of this study is to analyse
selected ARGOS stars using new high-resolution (R~45,000) and
high-signal-to-noise (S/N >100) spectra. We aim to derive their stellar
parameters and elemental ratios, in particular the abundances of C, N, the
alpha-elements O, Mg, Si, Ca, and Ti, the odd-Z elements Na and Al, the
neutron-capture s-process dominated elements Y, Zr, La, and Ba, and the
r-element Eu. Methods. High-resolution spectra of five field giant stars were
obtained at the 8m VLT UT2-Kueyen telescope with the UVES spectrograph in
FLAMES-UVES configuration. Spectroscopic parameters were derived based on the
excitation and ionization equilibrium of Fe I and Fe II. The abundance analysis
was performed with a MARCS LTE spherical model atmosphere grid and the
Turbospectrum spectrum synthesis code.
