# Copyright (c) 2017, 2018 ETH Zurich, Luca Tortorelli

The images are simulated with UFig. UFig employs a hybrid simulation approach, simulating stars directly on the pixel grid, and the galaxies by sampling the distributions photon-by-photon. This approach, numerical optimizations, and tools such as
HOPE make the image simulation process ultra-fast. Its performance (~3 min for a 0.5 sq. deg image) in simulating one image is comparable to running Source Extractor on this image.

At fixed field (e.g., 0959.0205), we simulate all the 40 NB images.

Exposure times, gains, saturation levels, magnitude zero-points, seeings, background noise amplitudes and sigmas and astrometric properties for each simulated image are taken from the corresponding PAUS real ones.

Galaxies and stars positions, sizes (rescaled due to the different pixel scale) and light profiles are taken from the simulated Subaru image overlapping with the considered PAUS image. Same applies to the redshift of the object.

Subaru galaxy magnitudes are computed assigning a certain weight to 5 SDSS template spectra and then integrating in the corresponding waveband. In PAUS, we use object by object the same coefficients of the template spectra, but integrating in the
correspondent NB.

Stars are taken from the Besancon catalogue, but preserving positions and sizes (rescaled) of the stars in the simulated Subaru images (also taken from the Besancon catalogue). Star magnitudes are kept fixed at those of the simulated Subaru images.

More details on the image simulation can be found in Tortorelli et al. 2018, Berge et al. 2013 and in Bruderer et al. 2016.

We provide also the detection image (*sim.detect.fits) for each PAUS simulated image.