Skyrmions and bags in the 2D-O(3) model

We investigate the 15N(alfa , gamma)19F and 15O(alfa , gamma)19Ne reactions by using a multicluster description of 15N and 15O. The 15N(alfa, gamma)19F and 15O(alfa , gamma )19Ne wave functions are defined in the Generator Coordinate Method, using alfa and triton (or 3He) wave functions. The band structure and the E2 transition probabilities are well reproduced by the model, but some resonances, important for astrophysics, are missing. The non-resonant part of the 15N(alfa , gamma)19F and 15O(alfa , gamma)19Ne capture cross sections is discussed.