Constraining the Expansion History and Early Dark Energy with Line Intensity Mapping

TL;DR

This paper explores how future line intensity mapping experiments targeting CO and [CII] lines can measure BAO at high redshifts (3<z<6), providing new constraints on the universe's expansion and early dark energy models.

Contribution

It assesses the potential of upcoming IM experiments to measure BAO at high redshifts, offering a novel approach to constrain early dark energy.

Findings

Future IM experiments could measure BAO scale to 5% or better.

High-redshift BAO measurements can provide competitive constraints on early dark energy.

Map depths required for CO and [CII] lines are identified for effective BAO detection.

Abstract

We consider the potential for line intensity mapping (IM) experiments to measure the baryon acoustic oscillations (BAO) from 3 < z < 6. This would constrain the expansion history in a redshift range that is currently unexplored. We calculate the map depths that future IM experiments targeting the CO(1-0) rotational transition line and [CII] ionized carbon fine-structure line would need to achieve in order to measure the BAO. We find that near-future IM experiments could constrain the BAO scale to 5% or better depending on CO/[CII] model amplitude. This measurement is at a precision that could make competitive constraints on models of early dark energy.