Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy

TL;DR

This paper proposes using 21 cm intensity mapping of baryon acoustic oscillations as a cost-effective method to study dark energy, potentially enabling large-scale radio sky surveys to understand cosmic acceleration.

Contribution

It introduces a novel approach of using 21 cm brightness intensity mapping for BAO measurements to test dark energy, offering a more economical alternative to galaxy redshift surveys.

Findings

Feasibility of 21 cm intensity mapping for BAO detection.

Potential for large-scale, cost-effective dark energy experiments.

Lays groundwork for future radio sky mapping initiatives.

Abstract

The expansion of the universe appears to be accelerating, and the mysterious anti-gravity agent of this acceleration has been called ``dark energy''. To measure the dynamics of dark energy, Baryon Acoustic Oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as $10^9$ individual galaxies, by observing the 21cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.