Pure source differential number counts (black data-point) at 850 and 450 μm around the ELAN MAMMOTH-1 compared to the simulated mean counts (red dashed line). The yellow shadings represent the 90% confidence range obtained from 500 realizations of the blue dot-dashed curves. The blue dot-dashed curves are the final adopted underlying models for the Monte Carlo simulations (see Sect. 4), and represent the true number counts. The dashed vertical lines indicate the mean 4σ within the effective area. The horizontal errorbars for the data-points indicate the width of each flux bin.