Forecasts on the Dark Energy and Primordial Non-Gaussianity Observations with the Tianlai Cylinder Array

TL;DR

This paper forecasts the Tianlai cylinder array's potential to observe large scale structures and constrain dark energy and primordial non-Gaussianity using 21 cm intensity mapping, BAO, RSD, and bispectrum analyses.

Contribution

It provides the first detailed forecasts of Tianlai's capabilities in measuring dark energy parameters and primordial non-Gaussianity with different array configurations.

Findings

Full-scale Tianlai can constrain dark energy parameters with -21 precision.

It can measure local non-Gaussianity parameter  with , and equilateral with .

Forecasts include capabilities of the pathfinder and upgraded array configurations.

Abstract

The Tianlai experiment is dedicated to the observation of large scale structures (LSS) by the 21 cm intensity mapping technique. In this paper we make forecasts on its capability at observing or constraining the dark energy parameters and the primordial non-Gaussianity. From the LSS data one can use the baryon acoustic oscillation (BAO) and the growth rate derived from the redshift space distortion (RSD) to measure the dark energy density and equation of state. The primordial non-Gaussianity can be constrained either by looking for scale-dependent bias in the power spectrum, or by using the bispectrum. Here we consider three cases: the Tianlai cylinder array pathfinder which is currently being built, an upgrade of the pathfinder array with more receiver units, and the full-scale Tianlai cylinder array. Using the full-scale Tianlai experiment, we expect $\sigma_{w_0} \sim 0.082$ and $\sigma_{w_a} \sim 0.21$ from the BAO and RSD measurements, $\sigma_{\rm f_{NL}}^{\rm local} \sim 14$ from the power spectrum measurements with scale-dependent bias, and $\sigma_{\rm f_{NL}}^{\rm local} \sim 22$ and $\sigma_{\rm f_{NL}}^{\rm equil} \sim 157$ from the bispectrum measurements.