  We give evidence of a clear structural signature of the glass transition, in
terms of a static correlation length with the same dependence on the system
size which is typical of critical phenomena. Our approach is to introduce an
external, static perturbation to extract the structural information from the
system's response. In particular, we consider the transformation behavior of
the local minima of the underlying potential energy landscape (inherent
structures), under a static deformation. The finite-size scaling analysis of
our numerical results indicate that the correlation length diverges at a
temperature $T_c$, below the temperatures here the system can be equilibrated.
Our numerical results are consistent with random first order theory, which
predicts such a divergence with a critical exponent $\nu=2/3$ at the Kauzmann
temperature, where the extrapolated configurational entropy vanishes.
