  This paper aims at providing a comprehensive framework to generate an
astrophysical scene and to simulate realistic hyperspectral and multispectral
data acquired by two JWST instruments, namely NIRCam Imager and NIRSpec IFU. We
want to show that this simulation framework can be resorted to assess the
benefits of fusing these images to recover an image of high spatial and
spectral resolutions. To do so, we create a synthetic scene associated with a
canonical infrared source, the Orion Bar. This scene combines pre-existing
modelled spectra provided by the JWST Early Release Science Program 1288 and
real high resolution spatial maps from the Hubble space and ALMA telescopes. We
develop forward models including corresponding noises for the two JWST
instruments based on their technical designs and physical features. JWST
observations are then simulated by applying the forward models to the
aforementioned synthetic scene. We test a dedicated fusion algorithm we
developed on these simulated observations. We show the fusion process
reconstructs the high spatio-spectral resolution scene with a good accuracy on
most areas, and we identify some limitations of the method to be tackled in
future works. The synthetic scene and observations presented in the paper are
made publicly available and can be used for instance to evaluate instrument
models (aboard the JWST or on the ground), pipelines, or more sophisticated
algorithms dedicated to JWST data analysis. Besides, fusion methods such as the
one presented in this paper are shown to be promising tools to fully exploit
the unprecedented capabilities of the JWST.
