A Robust BAO Extractor
  We define a procedure to extract the oscillating part of a given nonlinear
Power Spectrum, and derive an equation describing its evolution including the
leading effects at all scales. The intermediate scales are taken into account
by standard perturbation theory, the long range (IR) displacements are included
by using consistency relations, and the effect of small (UV) scales is included
via effective coefficients computed in simulations. We show that the UV effects
are irrelevant in the evolution of the oscillating part, while they play a
crucial role in reproducing the smooth component. Our "extractor" operator can
be applied to simulations and real data in order to extract the Baryonic
Acoustic Oscillations (BAO) without any fitting function and nuisance
parameter. We conclude that the nonlinear evolution of BAO can be accurately
reproduced at all scales down to $z=0$ by our fast analytical method, without
any need of extra parameters fitted from simulations.
