Enabling Next Generation Dark Energy and Epoch of Reionization Radio Observatories with the MOFF Correlator

TL;DR

This paper introduces the MOFF correlator, a novel imaging technique that significantly reduces computational costs for large radio arrays studying the epoch of reionization and dark energy, while providing fully calibrated widefield images.

Contribution

The paper presents the MOFF correlator, a new variation of direct imaging correlator that overcomes limitations of existing methods and enhances efficiency for large-scale radio cosmology arrays.

Findings

MOFF correlator is more efficient than traditional XF/FX correlators.

It provides fully calibrated widefield images including polarimetry.

No constraints on antenna arrangement or type.

Abstract

Proposed 21 cm cosmology observatories for studying the epoch of reionization (z ~6-15) and dark energy (z ~0-6) envision compact arrays with tens of thousands of antenna elements. Fully correlating this many elements is computationally expensive using traditional XF or FX correlators, and has led some groups to reconsider direct imaging/FFT correlators. In this paper we develop a variation of the direct imaging correlator we call the MOFF correlator. The MOFF correlator shares the computational advantages of a direct imaging correlator, while avoiding a number of its shortcomings. In particular the MOFF correlator makes no constraints on the antenna arrangement or type, provides a fully calibrated output image including widefield polarimetry and non-coplanar baseline effects, and can be orders-of-magnitude more efficient than XF or FX correlators for compact radio cosmology arrays.