MASSARI, DAVIDEDAVIDEMASSARILapenna, EmilioEmilioLapennaBRAGAGLIA, AngelaAngelaBRAGAGLIADalessandro, EmanueleEmanueleDalessandroContreras Ramos, RodrigoRodrigoContreras RamosAmigo, PíaPíaAmigo2020-04-292020-04-2920160035-8711http://hdl.handle.net/20.500.12386/24342We present Strömgren photometry of the Galactic Globular Cluster M3 to study its multiple generations phenomenon. The use of different colour-magnitude diagrams (CMDs) and especially of the notoriously efficient c<SUB>y</SUB> index allowed us to detect a double red giant branch in the cluster CMD. After decontamination from fore- and background sources, the two sequences turned out to be equally populated. The two components also show a bimodal radial distribution well corresponding to that predicted by numerical simulations for clusters living in an intermediate dynamical evolutive state and with a population with modified chemical composition that was born more centrally concentrated than the primordial. The analysis of high-resolution spectra quantitatively demonstrates that the two detected sequences correspond to the first (Na-poor) generation and the second (Na-rich) generation, thus confirming the importance of synergy between photometry and spectroscopy.STAMPAenArticle10.1093/mnras/stw5832-s2.0-84965002020000375799500061https://academic.oup.com/mnras/article/458/4/4162/26138552016MNRAS.458.4162MFIS/05 - ASTRONOMIA E ASTROFISICA