DECam Opens a New Window on the Galactic Bulge

The last decade has seen an era of intensive research on the Galactic bulge spearheaded by large spectroscopic surveys, such as the Bulge Radial Velocity Assay (BRAVA; [1], [2], [3]) and ARGOS [4], along with deep near-IR imaging campaigns such as VVV [5]. However, optical imaging remains an important tool for examining the formation history of the bulge since optical colors are more sensitive to stellar metallicity than the near-IR, and such observations are not as expensive as high-resolution spectroscopy. The modern era has lacked a uniform, deep, multi-band optical survey of the bulge, but the potential scientific return on such an analysis is too great to ignore. Motivated by these considerations, we undertook the Blanco DECam Bulge Survey (BDBS; [6], [7]), named in honor of the scientific contributions of Víctor and Betty Blanco, which is a survey of ~200 square degrees of the Southern bulge (Figure 1) using the mainly US Department of Energy (DOE)-funded Dark Energy Camera (DECam) on the Víctor M. Blanco 4m telescope and imaging in its ugrizY passbands