README.md

UNIONS Cosmological Inference Pipeline

by Lisa Goh and Sacha Guerrini, CEA Paris-Saclay

This folder contains the files neccessary to run the cosmological inference pipeline on the UNIONS galaxy catalogues.

Requirements

To run the pipeline, one would need to have installed CosmoSIS and CosmoCov. To PSF leakage parameters, the fork of cosmosis-standard-library of Sacha Guerrini has to be used.

To Run

Run the bash script within this folder

$ ./pipeline.sh

with one of the following flags:

--pcf: This step runs the cosmo_val.py script to calculate the various 2 point correlation functions. It will also write the $\xi_{pm}$ correlation functions in a fits file.

--covmat: The covariance matrix is calculated here using CosmoCov, by reading in the ./cosmocov_config/cosmocov_{output_root}.ini file. Hence make sure the output_root here corresponds to the one entered in the prompt.

--inference: This step writes out the relevant ./cosmosis_config/cosmosis_{output_root}.ini file, in order to run CosmoSIS to conduct the cosmological inference. It also combines the data needed by CosmoSIS: the $\xi_{pm}$ fits files calculated in cosmo_val.py, the covariance matrix, and the nz catalogue, into a single .fits file. It also fetches the rho-statistics computed in cosmo_val.py to marginalize on PSF leakage parameters. To do so, specify the path to the cosmo_val outputs. Note that the Rho- and Tau-statistics have to be stored in a folder rho_tau_stats in this folder. If the 2PCF $\xi_{pm}$ are not found it will raise an Error to run cosmo_val. If the Rho- and Tau-statistics do not exist, the script will raise a Warning to run cosmo_val but will create a data vector without the Rho- and Tau-statistics.

--mcmc_process: You can finally analyse the chains with the MCMC.ipynb notebook.

This is the pipeline used to derive cosmological constraints with cosmic shear data from the UNIONS v1.4 catalogue.