Near-infrared photometry of four metal-rich bulge globular clusters: NGC 6304, 6569, 6637 and 6638

We present high-quality near-infrared (near-IR) photometry of four bulge metal-rich globular clusters, namely NGC 6304, 6569, 6637 and 6638. By using the observed colour-magnitude diagrams we derived photometric estimates of the cluster reddening and distance. We performed a detailed analysis of the red giant branch (RGB), presenting a complete description of its morphologic parameters and evolutionary features (bump and tip). Photometric estimates of the cluster metallicity were obtained using the updated data set (published by our group) linking metal abundance to a variety of near-IR indices measured along the RGB. The detection of the RGB bump and tip is also presented and briefly discusse