Image Details
 
                    Caption: Figure 6.
Significance with which a cluster (﹩{{R}_{c}}=100﹩ kpc, ﹩\beta =0.6﹩) can be detected for redshifts of ﹩z=0.2﹩, 0.6, 1.0, and 1.4 as a function of the net number of photons in an image with a typical exposure time of 60 ks. The two horizontal solid lines show the 2.5σ and 3σ significance levels. The upper X-axis shows the corresponding flux.
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