# Verifying the Australian MWA EoR pipeline I: 21-cm sky model and correlated measurement density

**Authors:** J. L. B. Line, C. M. Trott, J. H. Cook, B. Greig, N. Barry, C. H. Jordan  
**arXiv:** [2404.05140](https://arxiv.org/abs/2404.05140)  
**Date:** 2024-04-08  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2404.05140v1/

## Key points

- The AusEoRPipe is designed to disentangle 21-cm radiation emitted by gas surrounding the very first stars from contaminating foreground astrophysical sources.
- The focus of the paper is on building an accurate 21-cm sky model for use with WODEN simulation software to generate predictable 21-cm signal visibilities.
- The power spectrum estimator CHIPS successfully recovers the 21-cm signal in the absence of foregrounds.
- Gridding density correction factor of 2.651 is determined for estimating the resultant power spectrum, suitable for integrations equal to or greater than 30 minutes involving multiple primary beam pointings and LSTs.
- This study serves as a foundation for Paper II where AusEoRPipe will be tested in the presence of foregrounds and instrumental effects, contributing valuable insights into refining and validating the pipeline.

## Summary

In this paper, the authors present the first of two papers dedicated to verifying the Australian Epoch of Reionisation pipeline (AusEoRPipe) through simulation. The AusEoRPipe is designed to disentangle 21-cm radiation emitted by gas surrounding the very first stars from contaminating foreground astrophysical sources and has been in development for nearly a decade. The focus of this paper is on building an accurate 21-cm sky model that can be utilized by the WODEN simulation software to generate visibilities containing a predictable 21-cm signal. The authors verify that the power spectrum estimator CHIPS can successfully recover this signal in the absence of foregrounds. Additionally, they investigate how measurements in Fourier-space are correlated and how their gridded density impacts the power spectrum. Through Gaussian-noise simulations of the MWA phase I layout, the authors measure and fit for the effect of gridding density on estimating the resultant power spectrum. They determine a gridding density correction factor of 2.651, which is deemed appropriate for integrations equal to or greater than 30 minutes of data involving observations with multiple primary beam pointings and LSTs. The findings from this paper will serve as a foundation for Paper II, where the AusEoRPipe will be tested in the presence of foregrounds and instrumental effects. The detailed methodology outlined in this study includes constructing a compatible 21-cm sky model with WODEN, projecting it into celestial coordinates, testing its recovery using CHIPS, and analyzing how well it aligns with expected power spectra. Overall, this research contributes valuable insights into refining and validating the AusEoRPipe for accurately detecting and analyzing 21-cm radiation signals from early cosmic epochs amidst various astrophysical complexities.