  The production cross section of inclusive isolated photons has been measured
by the ALICE experiment at the CERN LHC in pp collisions at centre-of-momentum
energy of $\sqrt{s}=13$ TeV collected during the LHC Run 2 data-taking period.
The measurement is performed by combining the measurements of the
electromagnetic calorimeter EMCal and the central tracking detectors ITS and
TPC, covering a pseudorapidity range of $|\eta^{\gamma}|<0.67$ and a transverse
momentum range of $7<p_{\rm T}^{\gamma}<200$ GeV/$c$. The result extends to
lower $p_{\rm T}^{\gamma}$ and $x_{\rm T}^{\gamma} = 2p_{\rm
T}^{\gamma}/\sqrt{s}$ ranges, the lowest $x_{\rm T}^{\gamma}$ of any isolated
photon measurements to date, extending significantly those measured by the
ATLAS and CMS experiments towards lower $p_{\rm T}^{\gamma}$ at the same
collision energy with a small overlap between the measurements. The measurement
is compared with next-to-leading order perturbative QCD calculations and the
results from the ATLAS and CMS experiments as well as with measurements at
other collision energies. The measurement and theory prediction are in
agreement with each other within the experimental and theoretical
uncertainties.
