Tuesday

We present our comprehensive campaign to study stellar populations in the Galactic bulge using the well-established means of Strömgren photometry. To this end, we obtained photometry with the Hubble Space Telescope’s (HST) Wide Field Camera 3 and Advanced Camera for Surveys bands of the two bulge globular clusters NGC 6553 and NGC 6528 in an unprecedentedly large number of filters, namely eleven near-ultraviolet to near-infrared, narrow-, medium-, and wide-field filters. By using various photometric metallicity- and temperature sensitive indices, we were able to estimate the stellar metallicity of horizontal branch, red giant branch and main sequence stars. The ages of both clusters were determined using Dartmouth isochrones. The main aim of our study is to test for the actual presence of a young, metal-rich population and identifying candidate metal-poor stars in the bulge, which ultimately lets us constrain the age range of the entire cluster population and its surrounding field. Thus our findings are an ideal input for ongoing and future large-scale spectroscopic surveys such as the GES or 4MOST.