  The gluon propagator is investigated in Landau and in maximal center gauge
for the gauge group SU(2) by means of lattice gauge simulations. We find that
Gribov ambiguities arising from the implementation of Landau gauge have a small
influence on the propagator. In agreement with previous findings, we obtain
that the small momentum behavior is dominated by a mass, which is of order
$(1.48 \pm 0.05) \sqrt{\sigma}$, where $\sigma $ is the string tension. By
removing the confining vortices from the full Yang-Mills ensemble, we convert
full YM-theory into a theory which does not confine quarks. We find that in the
latter case the strength of the gluon propagator in the intermediate momentum
range is strongly reduced. The spectral functions which reproduce the numerical
data for the propagators are analyzed using a generalized Maximum Entropy
Method.
