Visualisation of the simulation used to estimate the rate of pre-SN precursors. The red triangles mark the upper limits (non-detections) of the prediscovery images of a SN in the sample, converted into solar luminosities. The blue curve is a Gaussian with a_p = −14.5 r-band absolute magnitudes and σ_p = 20 days, while the green curve is a smaller one with a_p = −12.5 mag and σ_p = 10 days. The quiescent luminosity of the progenitor is set at 1 × 10⁶ L_⊙, and is shown by the grey dashed line.