Grackle: a Chemistry and Cooling Library for Astrophysics

TL;DR

Grackle is an open-source library that offers comprehensive non-equilibrium chemistry and cooling models for astrophysical simulations, supporting multiple programming languages and UV backgrounds.

Contribution

It introduces a versatile, community-supported library integrating primordial chemistry, cooling, and radiation transfer for astrophysics simulations.

Findings

Supports non-equilibrium primordial chemistry and cooling for H, D, He

Provides interfaces for C, C++, and Python with ease of integration

Includes testing infrastructure and performance benchmarks

Abstract

We present the Grackle chemistry and cooling library for astrophysical simulations and models. Grackle provides a treatment of non-equilibrium primordial chemistry and cooling for H, D, and He species, including H2 formation on dust grains; tabulated primordial and metal cooling; multiple UV background models; and support for radiation transfer and arbitrary heat sources. The library has an easily implementable interface for simulation codes written in C, C++, and Fortran as well as a Python interface with added convenience functions for semi-analytical models. As an open-source project, Grackle provides a community resource for accessing and disseminating astrochemical data and numerical methods. We present the full details of the core functionality, the simulation and Python interfaces, testing infrastructure, performance, and range of applicability. Grackle is a fully open-source project and new contributions are welcome.