Galaxy distribution

You must specify in the simulation yaml file the path to an input galaxy distribution (gal_dist). This must be in fits format currently, and could be either a random set of positions in ra, dec or simulated galaxy positions taken from, e.g., an N-body simulation. The default file is built from positions in the Buzzard simulation, with two versions: one matches 'WL' number density and one ('_deep') is intended to include sub-detection objects and match the full WFIRST density. The code expects this file to have columns: ra, dec, where units are degrees.

Galaxy property distributions

You must specify in the simulation yaml file the path to an input galaxy property distribution (gal_sample). This must be in fits format currently, and defines the distribution of galaxy properties - this currently is based on CANDELS (see wiki here https://github.com/WFIRST-HLS-Cosmology/Documents/wiki/Home-Wiki). The code expects this file to have columns: fwhm (units assumed to be CANDELS pixels), redshift, and filter names, which should be represented in the dictionary filter_flux_dict in simulate.py where they are mapped to the 'standard' GalSim names. These are in units of magnitude.

Stellar distribution and fluxes

You must specify in the simulation yaml file the path to an input stellar sample (star_sample). This must be in fits format currently, and positions/fluxes are currently simulated using galaxia-0.7.2. The code expects this file to have columns: ra, dec, where units are degrees, and magnitudes with GalSim filter names. There is a convert_galaxia function in simulate.py that converts magnitudes from galaxia J to WFIRST filters. This should produce an appropriate distribution of stars for the galaxy and proper distributions of IR mags.

Survey dither strategy

You must specify in the simulation yaml file the path to an input survey dither strategy file (dither_file). This must be in fits format currently, and is taken from Chris' survey simulation code. The default file is converted from this for a 5yr survey simulation using the helper function convert_dither_to_fits. The code expects this file to have columns: ra, dec, date (J2000), pa (position angle), filter, where angular units are in degrees and filter_dither_dict_ dictionary maps the filter numbers in the dither file to standard GalSim names.