JWST GC Survey Design

Observations of the GC must balance sensitivity with saturation, completeness with crowding, and areal coverage with multiple wavelengths. The interstellar extinction ranges from Av of 30 to >100 mag. In the near-infrared (NIR), exinction decreases steeply with wavelength but can still vary up to 0.5 mag over a few arcseconds at 2.15 µm. At 4−5µm, foreground extinction reaches an overall minimum of∼1 mag. Therefore, NIRCam is a key facility to study the GC: (1) at 4−5 µm, it is 1E4 times more sensitive than any ground-based instrument; and (2) the angular resolution of JWST is only rivalled by adaptive optics-assisted cameras on 8 m-class telescopes. However, anisoplanatic effects hamper precision measurements with the latter and also limit their useful field-of-view to <0.25 arcmin squared. The field-of-view of NIRCam is almost 40 times larger. Full details of the survey plan and science goals can be found in the survey White Paper here.