About Synchronized Globular Cluster Formation over Supra-galactic Scales

Observational and theoretical arguments support the idea that violent events connected with AGN activity and/or intense star forming episodes played a significant role in the early phases of galaxy formation at high redshifts. Being old stellar systems, globular clusters seem adequate candidates to search for the eventual signatures that might have been left by those energetic phenomena. The analysis of the colour distributions of several thousands of globular clusters in the Virgo and Fornax galaxy clusters reveals the existence of some interesting and previously undetected features. A simple pattern recognition technique, indicates the presence of ``colour modulations'', distinctive for each galaxy cluster. These patterns were first found on composite samples of globular clusters in galaxies with to , and later, detected on some sub-samples of globulars associated with individual giant elliptical galaxies.