Rapid hydrodynamic expansion in relativistic heavy-ion collisions

Hydrodynamic expansion of the hot fireball created in relativistic Au-Au collisions at root s = 200 GeV in 3 + 1-dimensions is studied. We obtain a simultaneous, satisfactory description of the transverse momentum spectra, elliptic flow, and pion correlation radii for different collision centralities and different rapidities. Early initial time of the evolution is required to reproduce the interferometry data, which provide a strong indication of the early onset of collectivity. We can also constrain the shape of the initial energy density in the beam direction, with a relatively high initial energy density at the center of the fireball.