Time dependence of elliptic flow in ultrarelativistic Au + Au collisions

The freeze-out time dependence of the elliptic flow and the transverse radius rT dependence of elliptic flow at different freeze-out time are studied for non-central Au+Au collisions at √SNN=200 GeV with the Relativistic Quantum Molecular Dynamics model. We get the results that the elliptic flow decreases with the freeze-out time and the correlation between the elliptic flow and the transverse radius changes with the freeze-out time what could be explained with the pressure gradient. The transverse expansion velocity of particles emitted at the freeze-out time is adopted as a signal of the pressure gradient. (authors)