Skewness as a probe of Baryon Acoustic Oscillations
  In this study we show that the skewness S_3 of the cosmic density field
contains a significant and potentially detectable and clean imprint of Baryonic
Acoustic Oscillations. Although the BAO signal in the skewness has a lower
amplitude than second order measures like the two-point correlation function
and power spectrum, it has the advantage of a considerably lower sensitivity to
systematic influences. Because it lacks a direct dependence on bias if this
concerns simple linear bias, skewness will be considerably less beset by
uncertainties due to galaxy bias. Also, it has a weaker sensitivity to redshift
distortion effects. We use perturbation theory to evaluate the magnitude of the
effect on the volume-average skewness, for various cosmological models. One
important finding of our analysis is that the skewness BAO signal occurs at
smaller scales than that in second order statistics. For an LCDM spectrum with
WMAP7 normalization, the BAO feature has a maximum wiggle amplitude of ~3% and
appears at a scale of ~82Mpc/h. We conclude that the detection of BAO wiggles
in future extensive galaxy surveys via the skewness of the observed galaxy
distribution may provide us with a useful, and potentially advantageous,
measure of the nature of Dark Energy.
