THE UNRESOLVED GALAXIES WITH GAIA

Classification and parametrization of unresolved galaxies to be detected by Gala is the goal of our contribution to DPAC/CU8. Gaia will observe more than several times 10(6) unresolved galaxies seen almost as point sources. For the classification and parametrization of these sources we have undertaken the following tasks: a) providing libraries of synthetic galaxy spectra (produced under the PEGASE.2 code of galaxy evolution) and a semi-empirical library using observed galaxy spectra from SDSS data archive. b) Developping an appropriate algorithm called Unresolved Galaxy Classifier (UGC). The algorithm is being developed implementing the Support Vector Machines (SVM), a supervised training technique. This algorithm utilizes Gala simulated BP/RP galaxy spectra of our synthetic galaxy library.