The radiative monte carlo is initiated once the model is constructed.
Different line interactions
line_interaction_id == 0: scatter line_interaction_id == 1: downbranch line_interaction_id == 2: macro
During the monte-carlo run we collect two estimators for the radiation field:
where \(\epsilon, \nu\) are comoving energy and comoving frequency of a packet respectively.
To calculate the temperature and dilution factor we first calculate the mean intensity in each cell ( \(J = \frac{1}{4\pi\, \Delta t\, V} J_\textrm{estimator}\) )., [2].
The weighted mean frequency is used to obtain the radiation temperature. Specifically, the radiation temperature is chosen as the temperature of a black body that has the same weighted mean frequency as has been computed in the simulation. Accordingly,
where the evaluation comes from the mean value of
and so
With the radiation temperature known, we can then obtain our estimate for for the dilution factor. Our radiation field model in the nebular approximation is
i.e. a dilute blackbody. Therefore we use our value of the mean intensity derrived from the estimator (above) to obtain the dilution factor
There endeth the lesson.