Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/239957

Title

A 2 per cent distance to z = 0.35 by reconstructing baryon acoustic oscillations I: methods and application to the Sloan Digital Sky Survey

Author(s)

Padmanabhan, Nikhil;  Xu, Xiaoying;  Eisenstein, Daniel J.;  Scalzo, Richard;  Cuesta, Antonio J.;  Mehta, Kushal T.;  Kazin, Eyal

Abstract

We present the first application to density field reconstruction to a galaxy survey to undo the smoothing of the baryon acoustic oscillation (BAO) feature due to non-linear gravitational evolution and thereby improve the precision of the distance measurements possible. We apply the reconstruction technique to the clustering of galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) luminous red galaxy (LRG) sample, sharpening the BAO feature and achieving a 1.9 per cent measurement of the distance to z = 0.35. We update the reconstruction algorithm of Eisenstein et al. to account for the effects of survey geometry as well as redshift-space distortions and validate it on 160 LasDamas simulations. We demonstrate that reconstruction sharpens the BAO feature in the angle averaged galaxy correlation function, reducing the non-linear smoothing scale Σnl from 8.1 to 4.4 Mpc h−1. Reconstruction also significantly reduces the effects of redshift-space distortions at the BAO scale, isotropizing the correlation function. This sharpened BAO feature yields an unbiased distance estimate (<0.2 per cent) and reduces the scatter from 3.3 to 2.1 per cent. We demonstrate the robustness of these results to the various reconstruction parameters, including the smoothing scale, the galaxy bias and the linear growth rate. Applying this reconstruction algorithm to the SDSS LRG DR7 sample improves the significance of the BAO feature in these data from 3.3σ for the unreconstructed correlation function to 4.2σ after reconstruction. We estimate a relative distance scale DV/rs to z = 0.35 of 8.88 ± 0.17, where rs is the sound horizon and is a combination of the angular diameter distance DA and Hubble parameter H. Assuming a sound horizon of 154.25 Mpc, this translates into a distance measurement DV(z = 0.35) = 1.356 ± 0.025& 8201;Gpc. We find that reconstruction reduces the distance error in the DR7 sample from 3.5 to 1.9 per cent, equivalent to a survey with three times the volume of SDSS.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 427, no. 3 (Dec 2012), pp. 2132-2145

Publication year

2012

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

Cosmological parameters;  Cosmology observations;  Dark energy;  Distance scale;  Large-scale structure of Universe

Publisher

Wiley-Blackwell Publishing

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2012.21888.x

Copyright

Copyright © 2012 The Authors. Monthly Notices of the Royal Astronomical Society copyright © 2012 RAS.

Additional information

The authors acknowledge support from the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, the Higher Education Funding Council for England, a NASA grant NNX11AF43G, a NSF grant AST-0707725 and NASA grant NNX07AH11G.

Peer reviewed