Photometric properties of Stellar Populations in GGCs: a multi-wavelength approach

Globular star clusters are extremely important astrophysical objects since (1) they are prime laboratories for testing stellar evolution; (2) they are “fossils” from the epoch of galaxy formation, and thus important cosmological tools; (3) they serve as test particles for studying the dynamics of the Galaxy; (4) information on individual stars can provide constrains for stellar dynamic models; (5) they are the largest aggregates in which all post Main Sequence (MS) stars can be individually observed, and thus serve as fiducial templates for all the studies of the integrated light from distant stellar systems. In the framework of a long-term project devoted to a multi-band study of stellar populations in Galactic Globular Clusters I present a set of recent results of a systematic study of (1) the Red Giant Branch in the near-IR (J,K) and in the optical bands; (2) the Horizontal Branch and Blue Stragglers stars from midand far-UV observations obtained with HST.