Parameters¶

The following parameters can be specified in the parameter file passed to generate_cross_sections.py. If a parameter is not given in the parameter file, it uses a default value as defined in the read_parameter_file() function within generate_cross_sections.py.

Parameter	Description
`chimes_main_data_path`	Path to the `chimes_main_data.hdf5` data file from the `chimes-data` repository.
`cross_sections_data_path`	Path to the directory containing additional data files needed by `generate_cross_sections.py` (for example, the frequency-dependent cross sections for each species). These can be found in `chimes-tools/generate_cross_sections/data/`.
`spectrum_file`	Name of the text file that defines the shape of the UV spectrum. This needs to contain a list of data points specifying log10(E [Ryd]) in the first column and log10(J_nu [erg/s/sr/cm^2/Hz]) in the second column, where E and J_nu are the photon energy and specific intensity respectively. Lines that start with a `#` character are treated as comments and are ignored. We include an example that can be used as a template (see the Examples section).
`output_file`	Name of the output cross sections HDF5 file.
`spectrum_shape`	A string describing the shape of the spectrum that was used. This is added to the header information in the output cross sections file.
`version_date`	A string giving the date when the cross sections file was created. This is added to the header information in the output file.
`rt_coupling_flag`	Integer flag (`0` or `1`) that determines whether RT coupling is enabled. This affects the photon energy range over which the cross sections and photon energies are defined (see the Coupling to a Radiative Transfer Solver section for details). This flag is also added to the header information in the output file.
`rt_HII_` `recombination_flag`	Integer flag (`0` or `1`) that specifies whether photons from the recombination of HII are included in this energy bin. Only used if if RT coupling is switched on. This flag is also added to the header information in the output file.
`rt_HeII_` `recombination_flag`	Integer flag (`0` or `1`) that specifies whether photons from the recombination of HeII are included in this energy bin. Only used if if RT coupling is switched on. This flag is also added to the header information in the output file.
`rt_E_min_eV`	Minimum photon energy in this energy bin, in eV. Only used if RT coupling is switched on. This parameter is also added to the header information in the output file.
`rt_E_max_eV`	Maximum photon energy in this energy bin, in eV. Only used if RT coupling is switched on. This parameter is also added to the header information in the output file.