Year: 2014
Type: article
Abstract: The baryon acoustic oscillation (BAO), known as one of the largest cosmological objects, is now recognized as a standard cosmological tool to measure geometric distances via the Alcock-Paczynski effect, by which the observed BAO exhibits characteristic anisotropies in addition to the redshift distortions. This implies that once we know the correct distances to the observed BAO, the tip points of baryon acoustic peaks in the anisotropic correlation function of galaxies, $\ensuremath{\xi}(\ensuremath{\sigma},\ensuremath{\pi})$, can form a great circle (hereafter the two-dimensional BAO circle) in the $\ensuremath{\sigma}$ and $\ensuremath{\pi}$ plane, where $\ensuremath{\sigma}$ and $\ensuremath{\pi}$ are the separation of the galaxy pair parallel and perpendicular to the line of sight, respectively. This two-dimensional BAO circle remains unchanged under the variations of the unknown galaxy bias and/or coherent motion, while it varies transversely and radially with respect to the variations of ${D}_{A}$ and ${H}^{\ensuremath{-}1}$, respectively. Hereby the ratio between the transverse distance ${D}_{A}$ and the radial distance ${H}^{\ensuremath{-}1}$ reproduces the intrinsic shape of the two-dimensional BAO circle, which is a priori given by the known broadband shape of spectra. All BAO peaks of $\ensuremath{\xi}(\ensuremath{\sigma},\ensuremath{\pi})$ are precisely calculated with the improved theoretical model of redshift distortion. We test this broadband Alcock-Paczynski method using baryon oscillation spectroscopic survey--like mock catalogues. The transverse and radial distances are probed in precision of several percentage fractional errors, and the coherent motion is observed to match with the fiducial values accurately.
Authors: Yong-Seon Song, Teppei Okumura, Atsushi Taruya
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2046417446