JEDI Science:

JEDI will probe the nature of dark energy in three independent ways:
(1) using Type Ia supernovae as cosmological standard candles over a range of distances (data: around 14,000 type Ia supernovae with redshifts ranging from 0 to 2),
(2) using baryon acoustic oscillations as a cosmological standard ruler over a range of cosmic epochs (data: a spectroscopic redshift survey of 10-100 million galaxies over the redshift range of 0.5 to 2 over 1000-10000 square degrees), and
(3) mapping the weak gravitational lensing distortion by foreground galaxies of the images of background galaxies at different distances (data: a weak lensing survey over 1000-10000 square degrees with a median redshift of 1 to 1.5).

The challenge to solving the mystery of dark energy will not be the statistics of the data obtained, but the tight control of systematic effects inherent in the data. JEDI mission uses three powerful independent probes of dark energy to provide the redundancy critical for detecting and controlling systematic errors, and placing accurate and precise constraints on dark energy. In addition, JEDI can use galaxy clusters selected by their weak lensing shear as an additional dark energy probe to further tighten the dark energy constraints.

The great wealth of cosmological data from JEDI will not only illuminate the nature of dark energy, but will help us solve other fundamental problems in cosmology as well. These include the nature of dark matter, and the evolution of galaxies and large scale structure in the universe.