Sample light curves for M31 events in CFHT. Dashed lines indicate the background level and the prescribed detection levels, 7 σ and 42 σ, respectively. Solid lines show the true light curves, and are not fits. Top left: ﹩Q_{0}=7﹩, ﹩\delta =20﹩. Top right: ﹩Q_{0}=7﹩, ﹩\delta =100﹩. Bottom left: ﹩Q_{0}=42﹩, ﹩\delta =20﹩. Bottom right: ﹩Q_{0}=42﹩, ﹩\delta =100﹩.