21cmFAST is a semi-numerical code that produces 3D cosmological realisations of many
physical fields in the early Universe.
It is super-fast, combining the excursion set formalism with perturbation theory to
efficiently generate density, velocity, halo, ionization, spin temperature, 21-cm, and
even ionizing flux fields (see the above lightcones!).
It has been tested extensively against numerical simulations, with excellent agreement
at the relevant scales.
21cmFAST has been widely used, for example, by the MWA,
LOFAR, HERA,
and SKA teams to model the
large-scale cosmological 21-cm signal. The speed of 21cmFAST is important
to produce simulations that are large enough (several Gpc across) to represent modern
low-frequency observations.
Full documentation (with examples, installation instructions and full API reference) found at https://21cmfast.readthedocs.io.
To acknowledge the use of 21cmFAST, please see the
acknowledgements page.
- A discrete halo sampler allowing for the creation of lightcones of galaxy properties and the inclusion of stochasticity. These discrete sources are self-consistently used in the IGM calculations
- The Inclusion of the Sheth-Tormen conditional halo mass function.
- Re-designed input/output structures which prioritise transparency.
- Refactoring of several of the C backend files for much easier development.
- A lower-level testing framework for calculations done in the backend.
As of v3.0.0, 21cmFAST is conveniently wrapped in Python to enable more dynamic code.
See the Changelog for a
full list of changes.