Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning

TL;DR

This paper details the design, deployment, and commissioning of HERA Phase II, a radio array for studying the Epoch of Reionization, highlighting systematics and future upgrade plans.

Contribution

It presents the design and commissioning progress of HERA Phase II, including case studies on systematics relevant for future 21 cm cosmology arrays.

Findings

Identification of common systematics during commissioning

Progress towards near-complete deployment of HERA Phase II

Insights into contamination mitigation for future arrays

Abstract

This paper presents the design and deployment of the Hydrogen Epoch of Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements of the Epoch of Reionization. First results from the phase I array are published as of early 2022, and deployment of the phase II system is nearing completion. We describe the design of the phase II system and discuss progress on commissioning and future upgrades. As HERA is a designated Square Kilometer Array (SKA) pathfinder instrument, we also show a number of "case studies" that investigate systematics seen while commissioning the phase II system, which may be of use in the design and operation of future arrays. Common pathologies are likely to manifest in similar ways across instruments, and many of these sources of contamination can be mitigated once the source is identified.