Wide-field Multi-object Spectroscopy to Enhance Dark Energy Science from LSST

Understand

LSST will open new vistas for cosmology in the next decade, but it cannot reach its full potential without data from other telescopes.

• Cosmological constraints can be greatly enhanced using wide-field ($>20$ deg$^2$ total survey area), highly-multiplexed optical and near-infrared multi-object spectroscopy (MOS) on 4-15m telescopes.
• This could come in the form of suitably-designed large surveys and/or community access to add new targets to existing projects.
• First, photometric redshifts can be calibrated with high precision using cross-correlations of photometric samples against spectroscopic samples at $0 < z < 3$ that span thousands of sq.