TY - JOUR
T1 - VVV CL001
T2 - Likely the Most Metal-poor Surviving Globular Cluster in the Inner Galaxy
AU - Fernández-Trincado, José G.
AU - Minniti, Dante
AU - Souza, Stefano O.
AU - Beers, Timothy C.
AU - Geisler, Doug
AU - Bidin, Christian Moni
AU - Villanova, Sandro
AU - Majewski, Steven R.
AU - Barbuy, Beatriz
AU - Pérez-Villegas, Angeles
AU - Henao, Lady
AU - Romero-Colmenares, Mariá
AU - Roman-Lopes, Alexandre
AU - Lane, Richard R.
N1 - Publisher Copyright:
© 2021. The Author(s). Published by the American Astronomical Society.
PY - 2021/2/20
Y1 - 2021/2/20
N2 - We present the first high-resolution abundance analysis of the globular cluster VVV CL001, which resides in a region dominated by high interstellar reddening toward the Galactic bulge. Using H-band spectra acquired by the Apache Point Observatory Galactic Evolution Experiment, we identified two potential members of the cluster, and estimated from their Fe i lines that the cluster has an average metallicity of [Fe/H] =-2.45 with an uncertainty due to systematics of 0.24 dex. We find that the light-(N), -(O, Mg, Si), and Odd-Z (Al) elemental abundances of the stars in VVV CL001 follo w the same trend as other Galactic metal-poor globular clusters. This makes VVV CL001 possibly the most metal-poor globular cluster identified so far within the Sun's galactocentric distance and likely one of the most metal-deficient clusters in the Galaxy after ESO280-SC06. Applying statistical isochrone fitting, we derive self-consistent age, distance, and reddening values, yielding an estimated age of Gyr at a distance of kpc, revealing that VVV CL001 is also an old GC in the inner Galaxy. The Galactic orbit of VVV CL001 indicates that this cluster lies on a halo-like orbit that appears to be highly eccentric. Both chemistry and dynamics support the hypothesis that VVV CL001 could be an ancient fossil relic left behind by a massive merger event during the early evolution of the Galaxy, likely associated with either the Sequoia or the Gaia-Enceladus-Sausage structures.
AB - We present the first high-resolution abundance analysis of the globular cluster VVV CL001, which resides in a region dominated by high interstellar reddening toward the Galactic bulge. Using H-band spectra acquired by the Apache Point Observatory Galactic Evolution Experiment, we identified two potential members of the cluster, and estimated from their Fe i lines that the cluster has an average metallicity of [Fe/H] =-2.45 with an uncertainty due to systematics of 0.24 dex. We find that the light-(N), -(O, Mg, Si), and Odd-Z (Al) elemental abundances of the stars in VVV CL001 follo w the same trend as other Galactic metal-poor globular clusters. This makes VVV CL001 possibly the most metal-poor globular cluster identified so far within the Sun's galactocentric distance and likely one of the most metal-deficient clusters in the Galaxy after ESO280-SC06. Applying statistical isochrone fitting, we derive self-consistent age, distance, and reddening values, yielding an estimated age of Gyr at a distance of kpc, revealing that VVV CL001 is also an old GC in the inner Galaxy. The Galactic orbit of VVV CL001 indicates that this cluster lies on a halo-like orbit that appears to be highly eccentric. Both chemistry and dynamics support the hypothesis that VVV CL001 could be an ancient fossil relic left behind by a massive merger event during the early evolution of the Galaxy, likely associated with either the Sequoia or the Gaia-Enceladus-Sausage structures.
UR - http://www.scopus.com/inward/record.url?scp=85102336174&partnerID=8YFLogxK
U2 - 10.3847/2041-8213/abdf47
DO - 10.3847/2041-8213/abdf47
M3 - Article
AN - SCOPUS:85102336174
SN - 2041-8205
VL - 908
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L42
ER -