Grackle
A chemistry and radiative cooling library for astrophysical simulations
Grackle is an open-source chemistry and radiative cooling/heating library for astrophysical simulations and models (Smith et al., 2017). It provides a non-equilibrium primordial chemistry network for atomic and molecular hydrogen, helium, and deuterium species, tabulated cooling and photoheating rates from the Cloudy code for metals, and a treatment of the UV background and its self-shielding.
Originally spun out of the chemistry machinery in Enzo, Grackle is deliberately code-agnostic: it presents a simple C/Fortran/Python interface and is used as the cooling solver by many of the major simulation codes in the community. The image above shows a classic application — the radiative cooling rate of gas as a function of temperature.
Documentation is at grackle.readthedocs.io, and development happens openly on GitHub.