  We report measurements of the third harmonic coefficient of the azimuthal
anisotropy, v_3, known as triangular flow. The analysis is for charged
particles in Au+Au collisions at sqrtsNN = 200 GeV, based on data from the STAR
experiment at the Relativistic Heavy Ion Collider. Two-particle correlations as
a function of their pseudorapidity separation are fit with narrow and wide
Gaussians. Measurements of triangular flow are extracted from the wide
Gaussian, from two-particle cumulants with a pseudorapidity gap, and also from
event plane analysis methods with a large pseudorapidity gap between the
particles and the event plane. These results are reported as a function of
transverse momentum and centrality. A large dependence on the pseudorapidity
gap is found. Results are compared with other experiments and model
calculations.
