  We describe the uniform and staggered magnetization distributions around a
vacancy in a quantum critical two-dimensional S=1/2 antiferromagnet. The
distributions are delocalized across the entire sample with a universal
functional form arising from an uncompensated Berry phase. The numerical
results, obtained using quantum Monte Carlo simulations of the Heisenberg model
on bilayer lattices with up to approximately 10^5 spins, are in good agreement
with the proposed scaling structure. We determine the exponent eta'=0.40 +/-
0.02, which governs both the staggered and uniform magnetic structure away from
the impurity and also controls the impurity spin dynamics.
