Program: GS-2024A-FT-115

Narrow-band photometric imaging surveys are identifying a significant number of apparently extremely metal poor stars (EMPs, [Fe/H]< -3.0) which require spectroscopic follow-up to confirm and to calibrate these survey findings. The recently approved NOIRLab survey MAGIC is a prime example that is carrying out a large sky survey with DECam on the Blanco telescope at CTIO using the narrow-band CaIIK filter. The MAGIC survey is designed to optimize EMP discovery space for giant stars. We intend to explore extending the MAGIC discovery space into the warmer subgiant domain, provide a calibration between the subgiants-to-giant regime, and begin to create a cross-calibration between the various metallicity-sensitive photometric surveys by acquiring observations of a subset of stars spanning the two regimes and common to multiple surveys. We anticipate this will result in a large expansion of the EMP discovery space, creating new scientific studies of EMP statistics, formation, and nucleosynthesis in the early universe.