VVV CL001: Likely the Most Metal-Poor Surviving Globular Cluster in the Inner Galaxy

Understand

We present the first high-resolution abundance analysis of the globular cluster VVV~CL001, which resides in a region dominated by high interstellar reddening towards the Galactic Bulge.

• Using \textit{H}-band spectra acquired by the Apache Point Observatory Galactic Evolution Experiment (APOGEE), we identified two potential members of the cluster, and estimate 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), $\alpha$-(O, Mg, Si), and Odd-Z (Al) elemental abundances of the stars in VVV~CL001 follow 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.