The red histogram is the probability density function (PDF) of T_s values for real AGILE observations of the sources listed in Table 4. The black histogram is the PDF of the T_s values of a simulated Cygnus region with all the sources reported in Table 2 except Cyg X-3 that has zero flux. The notch in the distribution near T_s = 6 is caused by the switch between the fixed and the free position of the source in our analysis method. The red dotted line is the theoretical distribution, the green dashed line is the theoretical distribution, the cyan dotted-dashed line is the distribution.