  The quarkonium hadroproduction in association with a photon at high energies
provides a probe of the dynamics of the strong interactions as it is dependent
on the nuclear gluon distribution. Therefore, it could be used to constrain the
behavior of the nuclear gluon distribution in proton-nucleus and
nucleus-nucleus collisions. Such processes are useful to single out the
magnitude of the shadowing/antishadowing effects in the nuclear parton
densities. In this work we investigate the influence of nuclear effects in the
production of JPsi + photon and Upsilon + photon and estimate the transverse
momentum dependence of the nuclear modification factors. The theoretical
framework considered in the JPsi (Upsilon) production associated with a direct
photon at the hadron collider is the non-relativistic QCD (NRQCD) factorization
formalism.
