SNAP Candidate Standard Stars

SNAP ({Supernova Acceleration Probe}) proposes to investigate the dark energy in the Universe by observing over 2000 Type Ia supernovae to a redshift of z=1.7, with high precision and accurate absolute colors over the wavelength range between 0.4 to 1.70 &micro.

Although many of the same calibration principles and techniques as are used on the ground-based telescopes and with HST will be reused for the flux calibration of the SNAP instruments, SNAP calibration is much more challenging due to the large number of SNAP filters (9), detectors (72), and its need for fainter (V∼19) sets of spectrophotometric standard stars over the SNAP wavelength range.

We summarize our ongoing projects for the calibration of the SNAP candidate spectrophotometric standard stars, selected from the Sloan Digital Sky Survey, using the Double Imaging Spectrographs (optical) and the CorMass spectrograph (NIR) on the ARC 3.5-m telescope, and using the WIYN 0.9-m and 3.5-m telescopes.