log N − log S distribution of detectable SNRs (left) and all emitting SNRs (right) based on 100 Monte Carlo realisations following a Steiman-Cameron source distribution, E_max estimation considering Bell instabilities, K_ep = 10^−3.0, and η = 7%. The spectral index of the accelerated particles α varies from 4 to 4.4. Shaded areas indicate ± one standard deviation. Thick solid lines correspond to the HGPS limits (blue: identified SNRs; green: identified and unidentified sources associated with SNRs; orange: all unidentified sources). The hatched region shows the ideal region for the simulated SNRs: between the identified SNRs and the sources associated with SNRs.