GalSim-Euclid-Like

Helper functions to generate simulations of Euclid-like images using GalSim.

This repository contains information about the Euclid space telescope and survey that is needed to produce simulations using GalSim. Some of the information provided is approximate, aimed towards fast simulations rather than full accuracy in representation of Euclid images. Places where the information is only approximate are flagged and described in the docstring, and we particularly highlight that the PSF is only approximate; for details, see the docstring of the getPSF() method. This library should enable generation of Euclid-like images of sufficient fidelity for preliminary exploration of object detection, photometry, deblending, and joint analysis with ground-based observatories. For applications requiring high precision such as weak lensing, the higher fidelity simulations available within the Euclid Consortium should be used.

This repository includes two distinct packages:

• euclidlike: has basic observatory, instrumentation, and survey information for Euclid. This package can be used on its own along with GalSim to produce Euclid-like simulations.
• euclidlike_imsim: has configuration scripts to produce large-scale Euclid-like simulation runs based on the information in euclidlike. It is based heavily on roman_imsim.

References

For more information about GalSim, please see its README and documentation.

For more information about Euclid, please see the Euclid Consortium website and papers linked from there.

Attribution for software and data used by particular routines in this library is given in the docstring for the relevant routine.

Installation

The source code for GalSim-Euclid-Like has not been published to pypi. To install from source code:

git clone [email protected]:GalSim-developers/GalSim-Euclid-Like.git

and install by running:

conda create -n euclidlike python=3.10
cd GalSim-Euclid-Like
conda activate euclidlike
pip install .

Please view the Installation Instructions (in INSTALL.rst) for further details on how to install GalSim-Euclid-Like.

Downloading relevant data

The Euclid-like PSF is constructed from precomputed oversampled images on a grid in focal plane position and wavelength. To use the full FOV PSF within GalSim-Euclid-Like, the images must be downloaded by running:

$ euclidlike_download_psf

in the terminal after installation of GalSim-Euclid-Like. To install in an alternative directory to the default, use the --dir argument. Refer to the getPSF documentation for further details about the PSF.

Getting started

Please see the examples/ directory for demos illustrating the use of this code.

Communicating with the developers

Feel free to open a GitHub issue to reach the developers with questions, comments, and bug reports. New contributors are also welcome and can indicate their interest in developing this code base through the Issues.

Attribution

This software is open source and may be used according to the terms of its license.

When using this software, please provide the URL to the repository in the resulting paper or note. Once there is a Zenodo DOI or journal article, this README will be updated and we will ask those using the code in their research to cite the relevant journal article.