The Pristine Inner Galaxy Survey (PIGS) – V. A chemo-dynamical investigation of the early assembly of the Milky Way with the most metal-poor stars in the bulge

• DOI: 10.1093/mnras/stac3332
• Publication Date: 2022-11-17T03:39:59Z
• Authors: Federico Sestito; Kim A Venn; Anke Arentsen; David Aguado; Collin L Kielty; Carmela Lardo; Nicolas F Martin; Julio F Navarro; Else Starkenburg; Fletcher Waller; Raymond G Carlberg; Patrick François; Jonay I González ...; Georges Kordopatis; Sara Vitali; Zhen Yuan
• Keywords: Galaxy: evolution; Galaxy evolution; globular clusters; stars-abundances; stars: kinematics and dynamics; FOS: Physical sciences; stars: Population II; Astrophysics - Astrophysics of Galaxies; 01 natural sciences; 520; Galaxy: bulge; Astrophysics - Solar and Stellar Astrophysics; [SDU]Sciences of the Universe [physics]; Galaxy: formation; 13. Climate action; Astrophysics of Galaxies (astro-ph.GA); 0103 physical sciences; Galaxy: abundances; Solar and Stellar Astrophysics (astro-ph.SR)

ABSTRACT The investigation of the metal-poor tail in Galactic bulge provides unique information on early Milky Way assembly and evolution. A chemo-dynamical analysis 17 very stars (VMP, [Fe/H]<−2.0) selected from Pristine Inner Galaxy Survey was carried out based Gemini/GRACES spectra. chemistry suggests that majority our are similar to halo. Orbits calculated Gaia EDR3 imply these brought into during earliest assembly. Most have large [Na,Ca/Mg] abundances, thus show little evidence enrichment by pair-instability supernovae. Two (P171457 P184700) chemical abundances compatible with second-generation globular cluster stars, suggestive presence ancient now dissolved clusters inner Galaxy. One them (P171457) is extremely ([Fe/H]<−3.0) well below metallicity floor clusters, which supports growing for existence lower-metallicity Universe. third star (P180956, [Fe/H]∼−2) has low [Ba/Fe] its metallicity, consistent formation a system polluted only one or few low-mass Interestingly, orbit confined plane, like other found literature, been associated building blocks Way.