Corrections to scaling and critical amplitudes in SU(2) lattice gauge theory

We calculate the critical amplitudes of the Polyakov loop and its susceptib ility at the deconfinement transition of SU(2) gauge theory. To this end we carefully study the corrections to the scaling functions of the observable s coming from irrelevant exponents. As a guiding line for determining the c ritical amplitudes we use envelope equations derived from the finite size s caling formulae for the observables. The equations are then evaluated with new high precision data obtained on N-sigma(3) x 4 lattices for N-sigma = 1 2, 18, 26 and 36. We find different correction-to-scaling behaviours above and below the transition. Our result for the universal ratio of the suscept ibility amplitudes is C+/C- = 4.72(11) and agrees perfectly with a recent m easurement for the 3d Ising model.