Redshift-space Enhancement of Line-of-sight Baryon Acoustic Oscillations in the Sloan Digital Sky Survey Main-galaxy Sample
Abstract
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, splitting the sample into slices 2fdg5 on the sky in various rotations. Measuring two-dimensional 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) h -1 Mpc. Averaging only along the line of sight, we estimate its significance at a particular wavelet scale and location at 2.2σ. In a flat angular weighting in the (π, rp ) coordinate system, the noise level is suppressed, pushing the bump's significance to 4σ. 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.
- Publication:
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The Astrophysical Journal
- Pub Date:
- February 2011
- DOI:
- 10.1088/0004-637X/728/1/34
- arXiv:
- arXiv:1011.2481
- Bibcode:
- 2011ApJ...728...34T
- Keywords:
-
- large-scale structure of universe;
- methods: data analysis;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 17 pages, 27 figures. Minor changes to match final version accepted to ApJ