FastSound: Probing the Origin of the Cosmic Acceleration with the Subaru/FMOS Cosmological Redshift Survey

The FastSound project is a galaxy redshift survey for cosmology, which has been approved as a Strategic Program of the Subaru Telescope operated by National Astronomical Observatory of Japan. The project uses a new instrument FMOS (fiber multi object spectrograph), which is a near-infrared spectrograph having 400 fibers in 30 arcmin diameter field-of-view. The scientific goal is to test the theory of gravity on the cosmological scale for the first time at distant universe (redshift beyond one). Such a test will shed light on the problem of dark energy (or accelerating universe), which is the most serious, important, and fundamental problem in modern physical cosmology.

Quick Summary of the Survey

• 30 sq-deg in total, in the 4 fields of the Canada-France-Hawaii Telescope Legacy Survey Wide (CFHTLS-W).
• wavelength coverage: 1.45 - 1.65 um (the high resolution mode)
• redshift range: z ~ 1.2 - 1.5
• will get ~10,000 redshifts of H alpha emitting galaxies
• constrain structure growth rate f sigma_8 at z ~ 1.35 to 15% accuracy

Schedule

40 Subaru nights in 2 years have been awarded to us, and the survey has started in April 2012. The survey is expected to be complete around spring/summer in 2014.

The Name Stands for...

• FAST = FMOS Ankoku Sekai Tansa (暗黒世界探査, meaning "dark universe survey" in Japanese), or FMOS Acceleration Samping Test
• SOUND = Subaru Observation Understanding Nature of Dark energy