Thermal photons from $\pi \rho \text{ra}\pi \gamma$ revisited

We evaluate the photon spectra from the reaction $\pi \rho \text{ra}\pi \gamma$ for the exchange of $\pi$, $\rho$, $\omega$, $\varphi$ and $a_1$ as intermediary mesons. It is found that the contributions from the intermediary $a_1$ is more than any other meson exchange processes up to photon energies 2.5 GeV.