  We study the non-equilibrium aging behavior of the gauge glass model in three
dimensions at the critical temperature. We perform Monte Carlo simulations with
a Metropolis update, and correlation and response functions are calculated for
different waiting times. We obtain a multiplicative aging scaling of the
correlation and response functions, calculating the aging exponent $b$ and the
nonequilibrium autocorrelation decay exponent $\lambda_c/z_c$. We also analyze
the fluctuation-dissipation relationship at the critical temperature, obtaining
the critical fluctuation-dissipation ratio $X_\infty$. By comparing our results
with the aging scaling reported previously for a model of interacting flux
lines in the vortex glass regime, we found that the exponents for both models
are very different.
