  We investigate the production of direct photons in central Au-Au collisions
at the relativistic Heavy-Ion Collider (RHIC) at 200 GeV per nucleon,
considering all possible sources. We treat thermal photons emitted from a
quark-gluon plasma and from a hadron gas, based on a realistic thermodynamic
expansion. Hard photons from elementary nucleon-nucleon scatterings are
included: primordial elementary scatterings are certainly dominant at large
transverse momenta, but also secondary photons from jet fragmentation and
jet-photon conversion cannot be ignored. In both cases we study the effect of
energy loss, and we also consider photons emitted from bremsstrahlung gluons
via fragmentation.
