* Astronomy

Title: A Fossil Bulge Globular Cluster revealed by VLT Multi-Conjugate Adaptive Optics
Authors: Sergio Ortolani, Beatriz Barbuy, Yazan Momany, Ivo Saviane, Eduardo Bica, Lucie Jilkova, Gustavo Malta Salerno, Bruno Jungwiert

The globular cluster HP1 is projected on the bulge, very close to the Galactic center. The Multi-Conjugate Adaptive Optics (MCAO) Demonstrator (MAD) at the Very Large Telescope (VLT) allowed to acquire high resolution deep images that, combined with first epoch New Technology Telescope (NTT) data, enabled to derive accurate proper motions. The cluster and bulge field stellar contents were disentangled by means of this process, and produced unprecedented definition in the colour-magnitude diagrams for this cluster. The metallicity of [Fe/H] ~ -1.0 from previous spectroscopic analysis is confirmed, which together with an extended blue horizontal branch, imply an age older than the halo average. Orbit reconstruction results suggest that HP1 is spatially confined within the bulge.

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