Ray Data Extractions
This page explains the options for the extraction of ray-like data from simulations.
General Ray Parameters
The ray directions are set by the standard camera options. In addition, the following parameters affect how ray origins are selected:
origins_bbox
– List of ray origins (optional). [Units: bounding box]origin_bbox
– Common origin for rays (optional). [Units: bounding box]
Otherwise, the origin is taken from the group catalogs using the group
or subhalo
command line argument following the snapshot
argument:
fof_base
– Friends of friends base name (optional). [Default value: fof_subhalo_tab]black_hole_origin
– Flag to use the most massive black hole of the subhalo (optional). [Default value: false]lyman_alpha_origin
– Flag to use the Lyman-alpha subhalo catalog (optional). [Default value: false]
The following parameters control the start and length of the rays:
start_fvir
– Ray starting radius offset intended for halo origins. [Units: virial radius]start_cMpc
– Ray starting radius offset intended for halo origins. [Units: cMpc]length_kms
– Ray length proxy of Doppler shift induced by Hubble flow. [Units: km/s]length_bbox
– Ray length in special box units. [Units: bounding box]length_Mpc
– Ray length in physical units. [Units: Mpc]length_cMpc
– Ray length in comoving units. [Units: cMpc]impact_kpc
– Cylinder impact radius in physical units (optional optimization). [Units: kpc]
The following parameters control the ray output fields (note that density is always output):
output_dust
– Flag to output the dust metallicity. [Default value: true]output_metallicity
– Flag to output the metallicity. [Default value: true]output_HI
– Flag to output the HI fraction. [Default value: true]output_HeI
– Flag to output the HeI fraction. [Default value: false]output_HeII
– Flag to output the HeII fraction. [Default value: false]output_neutral
– Flag to output the neutral hydrogen abundance. [Default value: false]output_electrons
– Flag to output the electron abundance. [Default value: true]output_internal_energy
– Flag to output the internal energy. [Default value: true]output_SFR
– Flag to output the star formation rate. [Default value: true]output_parallel_velocity
– Flag to output the parallel velocity. [Default value: true]output_velocities
– Flag to output the full \((x,y,z)\) velocities. [Default value: false]output_acceleration
– Flag to output the full \((x,y,z)\) acceleration. [Default value: false]output_radiation
– Flag to output the photon density. [Default value: false]output_magnetic_field
– Flag to output the magnetic field. [Default value: false]output_metals
– Flag to output the metal species fractions. [Default value: false]output_metals_as_densities
– Flag to output the metal species as densities rather than fractions. [Default value: false]