Using the Long Wavelength Array to Search for Cosmic Dawn

TL;DR

This paper reports on using the Long Wavelength Array to search for the Cosmic Dawn 21-cm signal, aiming to validate previous potential detections and improve observational limits with a novel 256-element array.

Contribution

It presents initial limits from LWA-SV on the Cosmic Dawn signal and discusses future improvements, leveraging beamforming capabilities of a large antenna array.

Findings

First limits set by LWA-SV on the 21-cm Cosmic Dawn signal

Demonstrates the potential of a 256-element array for this search

Future plans to enhance detection sensitivity

Abstract

The search for the spectral signature of hydrogen from the formation of the first stars, known as Cosmic Dawn or First Light, is an ongoing effort around the world. The signature should present itself as a decrease in the temperature of the 21-cm transition relative to that of the Cosmic Microwave Background and is believed to reside somewhere below 100 MHz. A potential detection was published by the Experiment to Detect the Global EoR Signal (EDGES) collaboration with a profile centered around 78 MHz of both unexpected depth and width (Bowman et. al 2018; arXiv:1810.05912). If validated, this detection will have profound impacts on the current paradigm of structure formation within $\Lambda$CDM cosmology. We present an attempt to detect the spectral signature reported by the EDGES collaboration with the Long Wavelength Array station located on the Sevilleta National Wildlife Refuge in New Mexico, USA (LWA-SV). LWA-SV differs from other instruments in that it is a 256 element antenna array and offers beamforming capabilities that should help with calibration and detection. We report first limits from LWA-SV and look toward future plans to improve these limits.