In this paper we compute the collision strengths and their thermally-averaged
Maxwellian values for electron transitions between the fifteen lowest levels of
doubly-ionised cobalt, Co^{2+}, which give rise to forbidden emission lines in
the visible and infrared region of spectrum. The calculations also include
transition probabilities and predicted relative line emissivities. The data are
particularly useful for analysing the thermodynamic conditions of supernova
ejecta.Comment: 9 pages, 2 figures, 11 table