Decontamination of galaxy spectra using four dispersion directions

This paper addresses the problem of spectra decontamination in slitless spectroscopy in the context of the Euclid space mission. This problem can be treated as a source separation problem which consists of estimating a set of unknown sources from a set of their mixtures. We first present a mixing model linking observed data to source spectra that simultaneously takes into account four light dispersion directions of the grism, then we propose two methods to decontaminate the spectra from the mixed data. Exploitation of all these dispersion directions improves the estimation of the spectrum of an object of interest. Preliminary results obtained using realistic noisy data show the effectiveness of the proposed methods.