The DESI Experiment, a whitepaper for Snowmass 2013

TL;DR

The DESI experiment aims to map the universe's large-scale structure using spectroscopic surveys to improve understanding of dark energy, neutrino masses, and primordial inflation with unprecedented precision.

Contribution

This whitepaper details the DESI project's design, goals, and expected scientific impact, representing a major advance in dark energy research through large-scale spectroscopic mapping.

Findings

Plans to obtain spectra for over 30 million objects

Expected 1% level measurements of the distance scale

Projected constraints on cosmological models

Abstract

The Dark Energy Spectroscopic Instrument (DESI) is a massively multiplexed fiber-fed spectrograph that will make the next major advance in dark energy in the timeframe 2018-2022. On the Mayall telescope, DESI will obtain spectra and redshifts for at least 18 million emission-line galaxies, 4 million luminous red galaxies and 3 million quasi-stellar objects, in order to: probe the effects of dark energy on the expansion history using baryon acoustic oscillations (BAO), measure the gravitational growth history through redshift-space distortions, measure the sum of neutrino masses, and investigate the signatures of primordial inflation. The resulting 3-D galaxy maps at z<2 and Lyman-alpha forest at z>2 will make 1%-level measurements of the distance scale in 35 redshift bins, thus providing unprecedented constraints on cosmological models.