Simulations of a sky region at high Galactic declination at the ALMA observing frequencies, with 20 randomly distributed point sources with the same intensity added. In this case the point sources have a spectrum given by curve a₂ in Fig. 3. The PSFs are assumed to be Gaussian with a standard deviation of 3 pixels. Noise is Gaussian-white with standard deviation set to 0.12 times the standard deviation of the values in the corresponding noise-free maps. The PSFs are assumed to be Gaussian with a standard deviation of 3 pixels. The two bottom-right panels show the simulated point sources and their position on the 950  GHz map.