Redshift-Space Enhancement of Line-of-Sight Baryon Acoustic Oscillations
  in the SDSS Main-Galaxy Sample
  We show that redshift-space distortions of galaxy correlations have a strong
effect on correlation functions with distinct, localized features, like the
signature of the baryon acoustic oscillations (BAO). Near the line of sight,
the features become sharper as a result of redshift-space distortions. We
demonstrate this effect by measuring the correlation function in Gaussian
simulations and the Millennium Simulation. We also analyze the SDSS DR7
main-galaxy sample (MGS), splitting the sample into slices 2.5 degrees on the
sky in various rotations. Measuring 2D correlation functions in each slice, we
do see a sharp bump along the line of sight. Using Mexican-hat wavelets, we
localize it to (110 +/- 10) Mpc/h. Averaging only along the line of sight, we
estimate its significance at a particular wavelet scale and location at 2.2
sigma. In a flat angular weighting in the (pi,r_p) coordinate system, the noise
level is suppressed, pushing the bump's significance to 4 sigma. We estimate
that there is about a 0.2% chance of getting such a signal anywhere in the
vicinity of the BAO scale from a power spectrum lacking a BAO feature. However,
these estimates of the significances make some use of idealized Gaussian
simulations, and thus are likely a bit optimistic.
