WFIRST Science Investigation Team "Cosmology with the High Latitude Survey" Annual Report 2017

Understand

Cosmic acceleration is the most surprising cosmological discovery in many decades.

• Testing and distinguishing among possible explanations requires cosmological measurements of extremely high precision probing the full history of cosmic expansion and structure growth and, ideally, compare and contrast matter and relativistic tracers of the gravity potential.
• This program is one of the defining objectives of the Wide-Field Infrared Survey Telescope (WFIRST), as set forth in the New Worlds, New Horizons report (NWNH) in 2010.
• The WFIRST mission has the ability to improve these measurements by 1-2 orders of magnitude compared to the current state of the art, while simultaneously extending their redshift grasp, greatly improving control of systematic effects, and taking a unified approach to multiple probes that provide complementary physical information and cross-checks of cosmological results.