SWIFTGalaxy: a Python package to work with particle groups from SWIFT simulations

Abstract

SWIFTGalaxy is an open-source astrophysics module that extends SWIFTSimIO to analyses of particles belonging to individual galaxies simulated with SWIFT. It inherits from and extends the functionality of SWIFTSimIO's SWIFTDataset class. It understands the content of halo catalogues and therefore which particles belong to a galaxy or other group of particles, and its integrated properties. The particles occupy a coordinate frame that is enforced to be consistent, such that particles loaded on-the-fly will match e.g.~rotations and translations of particles already in memory. Intuitive masking of particle datasets is also enabled. Utilities to make working in cylindrical and spherical coordinate systems more convenient are also provided. Finally, tools to iterate efficiently over multiple galaxies are provided.