Requirement
pip install numpy
pip install astropy
pip install matplotlib
Programs
radiation_fields.py :
Description :
This program calculates the scaling factor of the radiation field G0 relative
to the data of an object or a set of objects radiating for given distances
A file containing my G0 values with the associated distance will then be created
Input parameters :
filename : str,
name of the .txt containing intensity (in erg cm-2 s-1 nm-1 sr-1) and wavelength (in nm) data
parsec : float,
distance in parsec from the star
star_radius : float,
star radius, in unit of solar radius
ISRF : bool,
Interstellar Radiation Field; if true, then the filename is a file for ISRF
if false, the radiation field of a star is studied
RF_list: bool,
If false, the calculation of G0 is done for a given distance,
if true, it is done for a hundred distances whose input distance
will correspond to a G0 of the order of 1e6
For the interstellar medium, the parameters star_radius, parsec and RF_list are no longer important; the part of the program executed will be independent of them
three_levels_model.py :
Description :
This program seeks to calculate how a neutral gas subjected to a radiation field
is heated, involving PAHs in the ionization of the gas. The expressions used are based on the model with 3 energy levels of the molecule, going from the neutral molecule (charge state Z=0) to the dication (charge state Z=2) by ionization.
Input parameters :
filename : str,
name of the file containing wavelength in nm and intensity of a star or of the interstellar medium
star_radius : float,
star radius, in unit of solar radius
t_gas : float,
gas temperature
n_e : float,
electron density in cm-3 (n_e = n_h * 1.6e-4, n_h : hydrogene density)
n_c : float,
number of carbon atoms in pah molecules (size of the PAH)
parsec : float,
distance in parsec from the star
fc_pah : float,
fraction of cosmic carbon locked in PAHs (default: 0.1)
ISRF : bool,
Interstellar Radiation Field; if true, then the filename is a file for ISRF
if false, the radiation field of a star is studied (default: False)
four_levels_modle.py :
Description :
his program does the same thing and has the same parameters as the program three_levels_model.py, the difference being that we add expressions related to the 4 energy levels model. This model consists in taking into account the anions, i.e. the PAHs in a charge state Z = -1.
These last two programs use the parameters returned by radiations_fields.py in its calculations
Useful files
2 files categories are usefull to run the programs :
First, cross-section data of each PAH for sizes ranging from minimum 24 C atoms to 66 C atoms with associated energy for each charge state of the molecule.
Here you can find :- the anions file
- the neutrals file
- the cations file
- the dications file
Then you have the files containing the data of the stars or the interstellar medium for different approximations. Each file has a column with wavelengths (in nm) associated with an intensity (in erg cm-2 s-1 nm-1 sr-1).
Here you can find :- ISRF file
- stars file