Absolute Flux Calibrations for the Nancy Grace Roman Space Telescope Coronagraph Instrument

The Nancy Grace Roman Space Telescope's (Roman) Coronagraph Instrument is a technology demonstration equipped to achieve flux contrast levels of up to 10(-9). This precision depends upon the quality of observations and their resultant on-sky corrections via an absolute flux calibration (AFC). Our plan utilizes 10 dim and 4 bright standard photometric calibrator stars from Hubble Space Telescope's (HST) CAL-SPEC catalog to yield a final AFC error of 1.94% and total observation time of similar to 22 minutes. Percent error accounts for systematic uncertainties (filters, upstream optics, quantum efficiency) in Roman component instrumentation along with shot noise for a signal to noise ratio (SNR) of 500.