Abstract
The first and the fourth harmonics in the azimuthal distributions of particles were discussed with respect to the reaction plane in Au + Au collisions at the BNL relativistic heavy ion collider (RHIC). The measurements employed large elliptic flow generated at RHIC. From the correlation of second and first harmonics, it was determined that second harmonic was positive or in-plane. It was found that the integrated fourth harmonic was about 10 magnitudes smaller than the second harmonic.