Measurement of neutral mesons in pp and Pb--Pb at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with ALICE

Neutral mesons such as $\pi^{0}$ and $\eta$ that decay into two photons can be reconstructed and identified in a wide transverse momentum ($p_{\rm T}$) range.
Therefore, they are excellent probes to study strong hadron suppression in AA collisions reflecting parton energy loss in quark-gluon plasma (QGP).
ALICE employs several complementary methods for the photon measurement, which are two different types of calorimeters, the Electro-Magnetic Calorimeter (EMCal) and the Photon Spectrometer (PHOS), and the reconstruction of external conversions in detector materials ($\gamma \rightarrow e^{+}e^{-}$).
Each of them has advantages, i.e. excellent momentum resolution in reconstruction of converted photons down to very low $p_{\rm T}$ and the high reconstruction efficiency and triggering capability of calorimeters.
The invariant yield of neutral mesons in pp and Pb--Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV and the nuclear modification factor $R_{\rm AA}$ will be presented.