The giant, horizontal, and asymptotic branches of Galactic globular clusters. I. The catalog, photometric observables, and features

A catalog including a set of the most recent color-magnitude diagrams (CMDs ) is presented for a sample of 61 Galactic globular clusters (GGCs). We use d this database to perform a homogeneous systematic analysis of the evolved sequences (namely, the red giant branch [RGB], horizontal branch [HB], and asymptotic giant branch [AGB]). Based on this analysis, we present (1) a n ew procedure to measure the level of the zero-age horizontal branch (V-ZAHB ) and a homogeneous set of distance moduli obtained by adopting the HE as s tandard candle; (2) an independent estimate for RGB metallicity indicators and new calibrations of these parameters in terms of both spectroscopic ([F e/H](CG97)) and global metallicity ([M/H], including also the a-element enh ancement), such that the set of equations presented can be used to simultan eously derive a photometric estimate of the metal abundance and the reddeni ng from the morphology and the location of the RGB in the (V,B-V) CMD; and (3) the location of the RGB bump tin 47 GGCs) and the AGE bump tin nine GGC s). The dependence of these features on metallicity is discussed. We find t hat by using the latest theoretical models and the new metallicity scales, the earlier discrepancy between theory and observations (similar to 0.4 mag ) completely disappears.