Determination of galactic globular clusters ages, by employing new evolutionary models computed with updated input physics and recent ground based and HST observations. The goal of the research project is to accurately determine absolute and relative ages of clusters by adopting different techniques, in order to put a firm constraint on the value of the Hubble constant and to find a decisive answer to the question, whether the bulk of the galactic globular cluster population is coeval or not, an issue of fundamental importance for formation scenario of our galaxy. Together with the standard techniques for determining cluster ages (difference in luminosity between Turn Off and Horizontal Branch, difference in color between Turn Off and the base of the Red Giant Branch), the data by the OGLE group on the masses of detached eclipsing binary systems populating the Turn Off region of globular clusters will be used in order to independently derive the ages (through the direct comparison with the masses populating the Turn Off of the theoretical isochrones); in addition, the recent HST observations of the hotter part of the cooling sequences of white dwarfs in globulars will be used in order to determine the distance modulus (by comparison with the corresponding theoretical sequences) and then the clusters ages (through the absolute observational Turn Off luminosity) in another independent way.
Training content (objective, benefit and expected impact)
More expertise in this research field through the computation of new stellar models, the careful analisys of observational data, and the use of two new techniques in order to determine the clusters ages. Also the interaction with the very active stellar evolution and cosmology groups at the host institution is important for the development of the research project, and it will provide to the applicant a broader and more interdisciplinary scientific background.
Links with industry / industrial relevance (22)