Progress in the Construction and Testing of the Tianlai Radio Interferometers

Abstract

The Tianlai Pathfinder is designed to demonstrate the feasibility of using wide field of view radio interferometers to map the density of neutral hydrogen in the Universe after the Epoch of Reionizaton. This approach, called 21 cm intensity-mapping, promises an inexpensive means for surveying the large-scale structure of the cosmos. The Tianlai Pathfinder presently consists of an array of three, 15 m × 40 m cylinder telescopes and an array of sixteen, 6 m diameter dish antennas located in a radio-quiet part of western China. The two types of arrays were chosen to determine the advantages and disadvantages of each approach. The primary goal of the Pathfinder is to make 3D maps by surveying neutral hydrogen over large areas of the sky in two different redshift ranges: first at 1.03 > z > 0.78 (700 − 800 MHz) and later at 0.21 > z > 0.12 (1170 − 1270 MHz). The most significant challenge to 21 cm intensity-mapping is the removal of strong foreground radiation that dwarfs the cosmological signal. It requires exquisite knowledge of the instrumental response, i.e. calibration. In this paper we provide an overview of the status of the Pathfinder and discuss the details of some of the analysis that we have carried out to measure the beam function of both arrays. We compare electromagnetic simulations of the arrays to measurements, discuss measurements of the gain and phase stability of the instrument, and provide a brief overview of the data processing pipeline.

Inflation and Early Dark Energy with a Stage II Hydrogen Intensity Mapping Experiment

“…Currently, with NSF support, the group hosts the Tianlai Analysis Center (TAC), which analyzes data for the Tianlai instrument in China. The current, "Pathfinder" version of Tianlai includes an array of 16, 6-meter diameter dishes and 3, 15 m x 40 m cylinder telescopes operating in the 650-1420 MHz range and acts as a useful test-bed instrument for future efforts [280]. Near-term goals include determining the optimal design of future arrays (cylinders, dishes or both), and detecting HI at low and high redshift (z ∼ 0.15 and 1.0).…”

sitoolbox: A package for Bayesian estimation of the isotropy violation in the CMB sky

“…Another emerging field in astronomy is the HI intensity mapping. Several intensity mapping surveys, like Tianlai (Das et al 2018;Chen 2012), HIRAX, FAST, GBT etc. are either mapping or planning to map the 21cm sky signal.…”

Gravitational waves × HI intensity mapping: cosmological and astrophysical applications

“…Other purpose-built experiments are taking data or will be build in the near future e.g. CHIME [17], FAST [18], BINGO [19], Tianlai [20] and HIRAX [21].…”