Improvements to the Search for Cosmic Dawn Using the Long Wavelength Array

Abstract

We present recent improvements to the search for the global Cosmic Dawn signature using the Long Wavelength Array station located on the Sevilleta National Wildlife Refuge in New Mexico, USA (LWA–SV). These improvements are both in the methodology of the experiment and the hardware of the station. An improved observing strategy along with more sophisticated temperature calibration and foreground modeling schemes have led to improved residual RMS limits. A large improvement over previous work using LWA–SV is the use of a novel achromatic beamforming technique which has been developed for LWA–SV. We present results from an observing campaign which contains 29 days of observations between March 10, 2021 and April 10, 2021. The reported residual RMS limits are six times above the amplitude of the potential signal reported by the Experiment to Detect the Global EoR Signature (EDGES) collaboration.