  We use angle-resolved photo-emission spectroscopy (ARPES) to explore the
electronic structure of single crystals of FeSe over a wide range of binding
energies and study the effects of strong electron-electron correlations. We
provide evidence for the existence of "Hubbard-like bands" at high binding
energies consisting of incoherent many-body excitations originating from Fe
$3d$ states in addition to the renormalized quasiparticle bands near the Fermi
level. Many high energy features of the observed ARPES data can be accounted
for when incorporating effects of strong local Coulomb interactions in
calculations of the spectral function via dynamical mean-field theory,
including the formation of a Hubbard-like band. This shows that over the energy
scale of several eV, local correlations arising from the on-site Coulomb
repulsion and Hund's coupling are essential for a proper understanding of the
electronic structure of FeSe and other related iron based superconductors.
