The Electromagnetically Isolated Global Signal Estimation Platform (EIGSEP)

TL;DR

EIGSEP is a novel instrument designed to measure the cosmic 21-cm signal with electromagnetically isolated components, utilizing a shaped bowtie antenna and advanced calibration methods for improved accuracy.

Contribution

The paper introduces EIGSEP, a new platform with innovative design and calibration techniques for precise measurement of the global 21-cm cosmic signal.

Findings

Initial deployment near Utah demonstrates effective site characteristics.

Calibration scheme incorporating beam mapping and interferometric cross-correlation.

Preliminary data shows promising signal detection capabilities.

Abstract

The Electromagnetically Isolated Global Signal Estimation Platform (EIGSEP) is a new instrument designed to measure the global 21-cm signal from Cosmic Dawn and the Epoch of Reionization, redshifted to frequencies below 250 MHz. To reduce spectral structure in the antenna beam associated with ground scattering, EIGSEP uses a shaped bowtie antenna suspended in a canyon 100 m above the ground. We describe the current system design of EIGSEP, including the rotating antenna platform, a transmitter antenna to characterise the beam of the bowtie antenna, and auxiliary ground antennas. We then discuss the EIGSEP calibration scheme, which incorporates traditional Dicke switching in the receiver, and novel approaches that include beam mapping, beam modulation, and interferometric cross-correlation. The instrument has been deployed near Marjum Pass, Utah, for testing and initial data collection. We discuss the site characteristics and present initial field measurements.