Right now this module contains but a function definition for the generation of noisy spectra. Ideally, the module would compute all galaxy-independent quantities only once and write them to disk. Only the final noise formula, containing the clean spectrum and the airmass, would be computed in Measure_Redshift.
We have two noise models: Poisson noise with a uniform SNR (Sim_Gal_Spec_Observed_Random) and Poisson noise with a SNR computed according to a more realistic model (Sim_Gal_Spec_Cunha). Note that Measure_Redshift needs to be told via a string parameter (see its ini file) which model to import.
The clean spectral flux densities are integrated over the spectrograph pixels using a specialized Rebinning function.