  A search is performed for new phenomena in events having a photon with high
transverse momentum and a jet collected in 36.7 fb$^{-1}$ of proton-proton
collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV recorded with the
ATLAS detector at the Large Hadron Collider. The invariant mass distribution of
the leading photon and jet is examined to look for the resonant production of
new particles or the presence of new high-mass states beyond the Standard
Model. No significant deviation from the background-only hypothesis is observed
and cross-section limits for generic Gaussian-shaped resonances are extracted.
Excited quarks hypothesized in quark compositeness models and high-mass states
predicted in quantum black hole models with extra dimensions are also examined
in the analysis. The observed data exclude, at 95% confidence level, the mass
range below 5.3 TeV for excited quarks and 7.1 TeV (4.4 TeV) for quantum black
holes in the Arkani-Hamed-Dimopoulos-Dvali (Randall-Sundrum) model with six
(one) extra dimensions.
