Imaging the space-time evolution of high energy nucleus-nucleus collisionswith bremsstrahlung

The bremsstrahlung produced when heavy nuclei collide is estimated for cent ral collisions at the Relativistic Heavy Ion Collider. Bremsstrahlung photo ns with energies below 100-200 MeV are sufficient to discern the gross feat ures of the space-time evolution of electric charge, if they can be separat ed from other sources of photons experimentally. This is illustrated explic itly by considering two very different models, one Bjorken-like, the other Landau-like, both of which are constructed to give the same final charge ra pidity distribution. [S0556-2813(99)06006-9].