The Phase II Murchison Widefield Array: Design Overview

TL;DR

The Phase II upgrade of the Murchison Widefield Array doubles the number of antennas, enhancing sensitivity, imaging, and calibration capabilities for advanced radio astronomy research.

Contribution

This paper presents the design and implementation details of the MWA Phase II upgrade, significantly expanding array size and capabilities for improved scientific performance.

Findings

Enhanced surface brightness sensitivity by a factor of ~3.5.

Doubled maximum baseline length, improving u,v coverage.

Order of magnitude reduction in noise floor of continuum images.

Abstract

We describe the motivation and design details of the "Phase II" upgrade of the Murchison Widefield Array (MWA) radio telescope. The expansion doubles to 256 the number of antenna tiles deployed in the array. The new antenna tiles enhance the capabilities of the MWA in several key science areas. Seventy-two of the new tiles are deployed in a regular configuration near the existing MWA core. These new tiles enhance the surface brightness sensitivity of the MWA and will improve the ability of the MWA to estimate the slope of the Epoch of Reionisation power spectrum by a factor of ~3.5. The remaining 56 tiles are deployed on long baselines, doubling the maximum baseline of the array and improving the array u,v coverage. The improved imaging capabilities will provide an order of magnitude improvement in the noise floor of MWA continuum images. The upgrade retains all of the features that have underpinned the MWA's success (large field-of-view, snapshot image quality, pointing agility) and boosts the scientific potential with enhanced imaging capabilities and by enabling new calibration strategies.