matvis: a matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays
Journal
RAS Techniques and Instruments
Journal Volume
4
Start Page
rzaf001
ISSN
2752-8200
Date Issued
2025
Author(s)
Abstract
Detection of the faint 21 cm line emission from the Cosmic Dawn and Epoch of Reionization will require not only exquisite control over instrumental calibration and systematics to achieve the necessary dynamic range of observations but also validation of analysis techniques to demonstrate their statistical properties and signal loss characteristics. A key ingredient in achieving this is the ability to perform high-fidelity simulations of the kinds of data that are produced by the large, many-element, radio interferometric arrays that have been purpose-built for these studies. The large scale of these arrays presents a computational challenge, as one must simulate a detailed sky and instrumental model across many hundreds of frequency channels, thousands of time samples, and tens of thousands of baselines for arrays with hundreds of antennas. In this paper, we present a fast matrix-based method for simulating radio interferometric measurements (visibilities) at the necessary scale. We achieve this through judicious use of primary beam interpolation, fast approximations for coordinate transforms, and a vectorized outer product to expand per-antenna quantities to per-baseline visibilities, coupled with standard parallelization techniques. We validate the results of this method, implemented in the publicly available matvis code, against a high-precision reference simulator, and explore its computational scaling on a variety of problems.
Subjects
algorithm
cosmology: diffuse radiation
dark ages
reionization
first stars
software: development
public release
simulations
techniques: interferometric
Publisher
Oxford University Press (OUP)
Type
journal article