The Hubble Sphere Hydrogen Survey

TL;DR

The paper proposes a cost-effective, all-sky hydrogen 21 cm emission survey using fixed cylindrical reflectors to map billions of galaxy redshifts, enabling precise study of dark energy evolution.

Contribution

It introduces a novel fixed cylindrical reflector design for large-scale, low-cost, all-sky hydrogen surveys to measure baryon acoustic oscillations.

Findings

Potential to measure about a billion redshifts.

Enhanced uniformity and coverage of the sky.

Significant improvement over current galaxy redshift datasets.

Abstract

An all sky redshift survey, using hydrogen 21 cm emission to locate galaxies, can be used to track the wavelength of baryon acoustic oscillations imprints from z ~ 1.5 to z = 0. This will allow precise determination of the evolution of dark energy. A telescope made of fixed parabolic cylindrical reflectors offers substantial benefit for such a redshift survey. Fixed cylinders can be built for low cost, and long cylinders also allow low cost fast fourier transform techniques to be used to define thousands of simultaneous beams. A survey made with fixed reflectors naturally covers all of the sky available from it's site with good uniformity, minimizing sample variance in the measurement of the acoustic peak wavelength. Such a survey will produce about a billion redshifts, nearly a thousand times the number available today. The survey will provide a three dimensional mapping of a substantial fraction of the Hubble Sphere.