Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies
Abstract
We present the large-scale correlation function measured from a spectroscopic sample of 46,748 luminous red galaxies from the Sloan Digital Sky Survey. The survey region covers 0.72 h-3 Gpc3 over 3816 deg2 and 0.16<z<0.47, making it the best sample yet for the study of large-scale structure. We find a well-detected peak in the correlation function at 100 h-1 Mpc separation that is an excellent match to the predicted shape and location of the imprint of the recombination-epoch acoustic oscillations on the low-redshift clustering of matter. This detection demonstrates the linear growth of structure by gravitational instability between z~1000 and the present and confirms a firm prediction of the standard cosmological theory. The acoustic peak provides a standard ruler by which we can measure the ratio of the distances to z=0.35 and z=1089 to 4% fractional accuracy and the absolute distance to z=0.35 to 5% accuracy. From the overall shape of the correlation function, we measure the matter density Ωmh2 to 8% and find agreement with the value from cosmic microwave background (CMB) anisotropies. Independent of the constraints provided by the CMB acoustic scale, we find Ωm=0.273+/-0.025+0.123(1+w0)+0.137ΩK. Including the CMB acoustic scale, we find that the spatial curvature is ΩK=-0.010+/-0.009 if the dark energy is a cosmological constant. More generally, our results provide a measurement of cosmological distance, and hence an argument for dark energy, based on a geometric method with the same simple physics as the microwave background anisotropies. The standard cosmological model convincingly passes these new and robust tests of its fundamental properties.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2005
- DOI:
- 10.1086/466512
- arXiv:
- arXiv:astro-ph/0501171
- Bibcode:
- 2005ApJ...633..560E
- Keywords:
-
- Cosmology: Cosmic Microwave Background;
- Cosmology: Cosmological Parameters;
- Cosmology: Observations;
- Cosmology: Distance Scale;
- Galaxies: Elliptical and Lenticular;
- cD;
- Cosmology: Large-Scale Structure of Universe;
- Astrophysics
- E-Print:
- Submitted to the ApJ. Additional pedagogical material and numerical data at http://cmb.as.arizona.edu/~eisenste/acousticpeak