MATCHING STELLAR POPULATION-MODELS TO BULGE GLOBULAR-CLUSTERS

We compare observed color-magnitude diagrams (CMDs) of the three metal -rich bulge globular clusters NGC 6553, NGC 6528, and Terzan 5, and in tegrated spectral energy distributions (SEDs) of NGC 6528, and 47 Tuc, to theoretical isochrones and model SEDs computed with the code of Br uzual & Chariot (1997, ApJ, in preparation, hereafter BC97). The BC97 models provide the evolution in time of the spectrophotometric propert ies of simple stellar populations (SSPs) for a wide range of stellar m etallicity, These models allow us to compare predictions based on diff erent sets of evolutionary tracks and various choices of the stellar s pectral libraries with observational data. We conclude that: (a) At le ast for solar metallicity models, the semi-empirical flux corrections applied by Lejeune et al. (1997, A&A, in press; 1997, A&A, in preparat ion) to available grids of synthetic stellar spectra improve the agree ment between population model predictions and observations. (b) The ad opted reddening and distance moduli for the three clusters seem well d etermined, since the theoretical isochrones fit quite well the observe d CMDs, (c) The overall metallicity of these clusters is close to sola r, (d) Based on our CMD and SED models we estimate that the ages of NG C 6553 and NGC 6528 must be approximate to 12+/-2 Gyr, These are the o nly two clusters in our sample with main sequence photometry. From the UV-optical SED of 47 Tuc we estimate an age of approximate to 14+/-2 Gyr. (C) 1997 American Astronomical Society.