Separation of galaxy spectra measured with slitless spectroscopy

Abstract

This paper investigates the problem of separating galaxy spectra resulting from the slitless spectroscopy system, which can e.g. be used in spatial missions like the WISP survey and the Euclid project. We first derive a physical mixing model linking observed data to source spectra, then simplify it to obtain two different approximate but realistic models. The first simplified model being entirely defined by a few parameters, we propose a semi-blind source separation method which estimates these model parameters together with the source spectra. The second simplified model is linear instantaneous, and has a special form which is used to propose a new blind source separation method exploiting the non-negativity and spatial sparsity of data, as well as the correlation of the target source spectra in different light dispersion directions. Both methods are tested on realistic simulated data and lead to very encouraging results, confirming their effectiveness.