  Tracing the cosmic evolution of the Baryonic Acoustic Oscillation (BAO) scale
with galaxy two point correlation functions is currently the most promising
approach to detect dark energy at early times. A number of ongoing and future
experiments will measure the BAO peak with unprecedented accuracy. We show
based on a set of N-Body simulations that the matter distribution is
anisotropic out to ~150 Mpc/h, far beyond the BAO scale of ~100M pc/h, and
discuss implications for the measurement of the BAO. To that purpose we use
alignment correlation functions, i.e., cross correlation functions between high
density peaks and the overall matter distribution measured along the
orientation of the peaks and perpendicular to it. The correlation function
measured along (perpendicular to) the orientation of high density peaks is
enhanced (reduced) by a factor of ~2 compared to the conventional correlation
function and the location of the BAO peak shifts towards smaller (larger)
scales if measured along (perpendicular to) the orientation of the high density
peaks. Similar effects are expected to shape observed galaxy correlation
functions at BAO scales.
