Photon spectral index Γ plotted against total flux S_{1−100 GeV} for the 439 2WHSP-FGL sources (in red), the 85 new detections with TS > 25 (filled-in blue), and for the 65 lower-significance detections with TS between 10 and 25 (blue outlines). The dashed lines represent the flux limit achieved by 3FGL-4 yr (red) and by our direct search based on 7.2 yr of data (blue) down to TS = 10.