  A role of the axial vector mesons, such as $K_1$ and $a_1$, on the emitted
photon spectrum in hot hadronic matter is studied through the channels $\pi
\rho \to a_1 \to \pi \gamma$ and $K \rho \to K_1 \to K \gamma$. They are shown
to be dominant channels in this spectrum. This study is carried out with an
effective chiral lagrangian which includes vector and axial-vector mesons and
explains well their relevant decays simultaneously.
