An optimal extraction of spatially blended spectra

We describe an algorithm to optimally extract individual spectra of blended sources from a long slit spectrum. A semi-analytic model for the spatial profile is used: a Voigt profile for the undersampled core with a numerical correction applied to the wings. This is derived from an isolated source which must also be placed on the slit. chi(2) fitting is used to separate the blended components with maximum weight given to the best data. We demonstrate the successful application of the algorithm to data on two X-ray binaries in crowded fields: XTE J2012+381 and V404 Cyg.