The radio telescope taps radio energy from near and far across the vast oceans of space. Some of its radio signals have been traced to colliding galaxies. Such a collision is a stupendous traffic accident between two giant star systems but, we think, the star; themselves do not crash into each other.
The stars, like those in our own galaxy, are widely separated and the spaces between them are often choked with clouds of dusty gases. When galaxies collide, we suspect, these high speed particles of dust and gas crash into each other resulting in terrific heat and radio energy.