Flows and polarization of early photons with magnetic field at strong coupling

Recent experimental results from RHIC and LHC on hard photon emission rates in heavy-ion collisions indicate a large azimuthal asymmetry of photon emission rate parameterized by the elliptic flow v_2. Motivated by a recent proposal that the early magnetic field created by two colliding heavy-ions may be responsible for this large azimuthal asymmetry of photon emission rate, we compute the azimuthal dependence of the photon emission rate from a strongly coupled finite temperature plasma with magnetic field in the framework of gauge/gravity correspondence. We also propose and compute a new observable, "in/out-plane polarization asymmetry", constructed from the polarization dependence of the photon emission rates. We observe that both the azimuthal and polarization asymmetry of photon emissions are strongly affected by the triangle anomaly (chiral anomaly) for low frequency regime below 1 GeV.