Measurement of identified pi^0 and inclusive photon v_2 and implication   to the direct photon production in sqrt(s_NN) = 200 GeV Au+Au collisions
  The azimuthal distribution of identified pi^0 and inclusive photons has been measured in sqrt{s_{NN}} = 200 GeV Au+Au collisions with the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). The second harmonic parameter (v_2) was measured to describe the observed anisotropy of the azimuthal distribution. The measured inclusive photon v_2 is consistent with the value expected for the photons from hadron decay and is also consistent with the lack of direct photon signal over the measured p_T range 1-6 GeV/c. An attempt is made to extract v_2 of direct photons. 
PHENIX Collaboration, S.S. Adler, et al