Collective flow measurements from the PHENIX experiment

Recent collective flow measurements including higher moment event anisotropy from the PHENIX experiment are presented, and the particle type, beam energy dependence and the relation with jet modification are discussed. The measured higher order event anisotropy with event plane defined at forward rapidities and the long-range correlation with large eta gaps are both consistent with initial geometrical fluctuation of the participating nuclei. In 200 GeV Au+Au collisions, higher order event anisotropy, especially simultaneous description of nu(2) and nu(3), is found to give an additional constraining power on an initial geometrical condition and viscosity in the hydrodynamic calculations. nu(2), nu(3) and nu(4) are almost unchanged down to the lower colliding energy at 39 GeV in Au+Au. The measured two-particle correlation with subtraction of the measured nu(n) parameters shows a significant effect on the shape and yield in the associate particle Delta phi distribution with respect to the azimuthal direction of trigger particles. However, some medium responses from jet suppression or jet modification seem to be observed. Direct photon nu(2) has been measured in 200 GeV Au+Au collisions. The measured nu(2) is found to be small at high p(T) as expected from non-suppressed direct photon R-AA similar or equal to 1, which can be understood as being dominated by prompt photons from initial hard scattering. On the other hand, at lower p(T) < 4 GeV/c it is found to be significantly larger than zero, which is comparable to other hadron nu(2), where thermal photons are observed.