The baryonic acoustic feature and large-scale clustering in the sloan digital sky survey luminous red galaxy sample

We examine the correlation function ξ of the Sloan Digital Sky Survey Luminous Red Galaxy sample at large scales (60 h ^-1 Mpc < s < 400h ^-1Mpc) using the final data release (DR7). Focusing on a quasi-volume-limited (0.16 < z < 0.36) subsample and utilizing mock galaxy catalogs, we demonstrate that the observed baryonic acoustic peak and larger scale signal are consistent with ΛCDM at 70%-95% confidence. Fitting data to a non-linear, redshift-space, template-based model, we constrain the peak position at s _p = 101.7 3.0h ^-1Mpc when fitting the range 60 h ^-1 Mpc < s < 150h ^-1Mpc (1σ uncertainties). This redshift-space distance s _p is related to the comoving sound horizon scale r_s after taking into account matter-clustering non-linearities, redshift distortions, and galaxy-clustering bias. Mock catalogs show that the probability that a DR7-sized sample would not have an identifiable peak is at least 10%. As a consistency check of a fiducial cosmology, we use the observed s _p to obtain the distance relative to the acoustic scale. We find r_s /D_V (z = 0.278) = 0.1389 0.0043. This result is in excellent agreement with Percival et al., who examine roughly the same data set, but use the power spectrum. Comparison with other determinations in the literature are also in very good agreement. The signal of the full sample at 125 h ^-1 Mpc < s < 200h ^-1Mpc tends to be high relative to theoretical expectations; this slight deviation can probably be attributed to sample variance. We have tested our results against a battery of possible systematic effects, finding all effects are smaller than our estimated sample variance.