Different Noise Realizations

Each simulation is based on a single realization of the thermal noise. The various indicators, particularly the fidelity indices, are in part attempts to combine a number of pixels to obtain a quick approximation to the range in accuracies which would be provided by running many simulations with different noise realizations. How well does this work in practice? Table 4a lists the results of five different runs of the same simulation (the largest version of Cyg A), each with a different realization of the thermal noise. While both the intensity-weighted mean and the high-SNR mean FI changed by factors of several from one simulation to the next, the peak median FI and the peak SNR were both constant to within 4%. These two indicators seem quite reliable.