Interferometric imaging with the 32 element Murchison Wide-field Array

TL;DR

This paper demonstrates interferometric imaging capabilities with a 32-element prototype of the Murchison Wide-field Array, showcasing real-time calibration and imaging techniques for low-frequency radio astronomy.

Contribution

It introduces a real-time calibration and imaging pipeline for the MWA prototype, enabling stable wide-field imaging at low frequencies.

Findings

Successful imaging of a 20-degree wide field centered on Pictoris A.

Demonstration of real-time calibration and imaging stability.

Validation of wide-field imaging techniques for low-frequency arrays.

Abstract

The Murchison Wide-field Array (MWA) is a low frequency radio telescope, currently under construction, intended to search for the spectral signature of the epoch of re-ionisation (EOR) and to probe the structure of the solar corona. Sited in Western Australia, the full MWA will comprise 8192 dipoles grouped into 512 tiles, and be capable of imaging the sky south of 40 degree declination, from 80 MHz to 300 MHz with an instantaneous field of view that is tens of degrees wide and a resolution of a few arcminutes. A 32-station prototype of the MWA has been recently commissioned and a set of observations taken that exercise the whole acquisition and processing pipeline. We present Stokes I, Q, and U images from two ~4 hour integrations of a field 20 degrees wide centered on Pictoris A. These images demonstrate the capacity and stability of a real-time calibration and imaging technique employing the weighted addition of warped snapshots to counter extreme wide field imaging distortions.