# Nyx snapshots: static density / temperature fields and halo catalogs

## File structure
There is one directory for each snapshot resolution. The name of the directory is the number of cells on each side of the simulation grid. E.g. the `512` directory is for 512^3, and the `1024` directory is for 1024^3.

Within each directory are `.raw` scalar field files and halo catalogs in `.txt` format.

## Scalar Fields
Density/temperature fields at each redshift are stored in binary files containing 3D arrays of floating-point numbers in column-major (Fortran) order.

Each file is named using the convention `z<redshift>_<field>_<precision>.raw`.
  * `redshift` is the redshift of the snapshot.
  * `field` is the scalar field, e.g. temperature, density.
  * `precision` is the floating-point numerical precision.

## Halo catalogs
Halo catalogs at each redshift are in `halocat_z<redshift>.txt`. They give the position (Mpc), mass (solar masses), and number of cells for each halo.