Using the Long Wavelength Array to Search for Cosmic Dawn

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[Formula: see text]cm transition relative to that of the Cosmic Microwave Background and is believed to reside somewhere below 100[Formula: see text]MHz. A potential detection was published by the Experiment to Detect the Global EoR Signal (EDGES) collaboration with a profile centered around 78[Formula: see text]MHz of both unexpected depth and width (Bowman et al. [2018] Nature 555, 67). If validated, this detection will have profound impacts on the current paradigm of structure formation within [Formula: see text]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 capabilisties that should help with calibration and detection. We report first limits from LWA-SV and look toward future plans to improve these limits.