Ratio between RATE of sim and detected sources

Figure 5.2: The measured value of source count rate was found to be systematically larger than the 'true' rate for all sources. This figure shows the ratio between the 'true' rate (labeled 'rate(sim)' on the vertical axis) and the detected rate for a single background+exposure model (5*10-7 counts/s/arcsec2 background and 47 ks exposure) as a function of detected count rate.

Note that the curve asymptotes to about 0.96 in the limit of high rate values. The reason for this is not known for certain but is probably due to differences between the point spread function (PSF) used to make the simulated images and that used by the detection software.