meer21cm: an Analysis Pipeline and Comprehensive Toolkit for HI Intensity Mapping

Abstract

We present meer21cm, a comprehensive python package for cosmological data analysis of single-dish HI intensity mapping surveys. This package is simple to use, with a modularised code structure designed for interactive usage. meer21cm is designed for data analysis, with particular focus on the UHF-band observation of MeerKAT Large Area Synoptic Survey (MeerKLASS). We explicitly impose meer21cm to be survey-oriented, ensuring consistent modelling of observational effects in the clustering power spectrum with the survey specifications and data analysis choices. meer21cm covers a large range of data analysis procedures post calibration, including data read-in, foreground cleaning, power spectrum estimation, mock simulation, transfer function corrections and parameter inference. It handles both meer21cm intensity maps and overlapping galaxy catalogues, allowing for multi-tracer and cross-correlation analysis between MeerKLASS and optical galaxy surveys. Tested with a simulated survey of ten $750$deg${}^2$ sky patches in the redshift sub-band $0.6<z<0.8$, the meer21cm pipeline achieves per-cent accuracy in the power spectrum estimation for $k\in [0.02,0.2]h{\mathrm{Mpc}}^{-1}$, with deviations $\lesssim 0.5\ddot{I}ƒ$ between the mock and the model power spectra, where $\ddot{I}ƒ$ is the signal variance. The meer21cm package is publicly available and easy to install, with a comprehensive documentation website at https://meer21cm.readthedocs.io

Prepared for submission to the Open Journal of Astrophysics