Verifying the reality of the line detection in EGS8p7. The signal-to-noise distribution from 1500 randomly positioned apertures across the 2D data presented in Figure 1. All of the apertures were 6 pixels in radius (﹩\simeq 7.5﹩ Å in wavelength space), similar to the aperture used to measure the line significance. The vertical line shows the detected signal to noise far exceeds that of the noise distribution.