Expanded Globular Cluster Database

The Expanded Globular Cluster Database (EGCD) is a comprehensive compilation of Milky Way globular cluster properties, combining catalog data from Harris (2010, 2015 update), Angeli et al. (2005), Petralia et al. (2017), Gaia DR3 astrometry, and new observational measurements. Each row corresponds to a single globular cluster, with over 70 variables describing positional, photometric, kinematic, and structural properties. Key variables include Galactic coordinates, heliocentric and galactocentric distances, metallicity ([Fe/H]), horizontal branch magnitude, integrated luminosities and colors, structural parameters (core radius, half-light radius, concentration, ellipticity), velocity dispersions, rotation measurements, relaxation times, age estimates, and derived quantities such as cluster density, dynamic mass, morphochemical indices, and rotation support parameters (V/σ). The EGCD is intended for reproducible research and analysis of Milky Way globular clusters, including studies of metallicity trends, rotational kinematics, luminosity modeling, and galactic formation history. Derived Cartesian coordinates (x, y, z) and Galactocentric distances were calculated using a solar position of R☉ = 8.2 kpc and z☉ = 20.8 pc, with all positional measurements referenced to J2000.0. Observational data from this study were processed using Deep Sky Stacker, Photopea, Google Sheets, and Python (matplotlib). The database is curated to ensure clarity and reproducibility. Selection criteria for inclusion were: clusters must have measured metallicity and distance; duplicates and conflicting entries were resolved by prioritizing high-resolution spectroscopic data (Petralia et al.), then Angeli et al., then Harris (2010). Clusters with unresolved conflicts or missing data were excluded. The resulting dataset contains N clusters suitable for statistical and observational analyses of globular cluster properties in relation to Galactic position.