GalSim: The modular galaxy image simulation toolkit

TL;DR

GALSIM is an open-source, modular toolkit for simulating high-precision astronomical images of stars and galaxies, supporting advanced transformations and operations crucial for weak lensing and upcoming dark energy surveys.

Contribution

It introduces a comprehensive, high-precision, open-source simulation library tailored for astronomical image analysis, meeting the needs of current and future large-scale surveys.

Findings

Meets high precision requirements for weak lensing analysis

Supports simulations for LSST, Euclid, and WFIRST missions

Provides extensive documentation and open-source code repository

Abstract

GALSIM is a collaborative, open-source project aimed at providing an image simulation tool of enduring benefit to the astronomical community. It provides a software library for generating images of astronomical objects such as stars and galaxies in a variety of ways, efficiently handling image transformations and operations such as convolution and rendering at high precision. We describe the GALSIM software and its capabilities, including necessary theoretical background. We demonstrate that the performance of GALSIM meets the stringent requirements of high precision image analysis applications such as weak gravitational lensing, for current datasets and for the Stage IV dark energy surveys of the Large Synoptic Survey Telescope, ESA's Euclid mission, and NASA's WFIRST-AFTA mission. The GALSIM project repository is public and includes the full code history, all open and closed issues, installation instructions, documentation, and wiki pages (including a Frequently Asked Questions section). The GALSIM repository can be found at https://github.com/GalSim-developers/GalSim .