Measurement of baryon acoustic oscillations in the Lyman-α forest fluctuations in BOSS data release 9

• Published in: Journal of cosmology and astroparticle physics Vol. 2013; no. 4; pp. 1 - 52
• Main Authors: Slosar, Anze, Irsic, Vid, Kirkby, David, Bailey, Stephen, Busca, Nicolas G, Delubac, Timothee, Rich, James, Aubourg, Eric, Bautista, Julian E, Bhardwaj, Vaishali
• Format: Journal Article
• Language: English
• Published: United States Institute of Physics (IOP) 01.04.2013
• Subjects: Acoustic measurement; Acoustics; Astrophysics; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BARYONS; CORRELATION FUNCTIONS; CORRELATIONS; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; Cosmology; Cosmology and Extra-Galactic Astrophysics; Dilation; ERRORS; FLUCTUATIONS; Forests; LYMAN LINES; Mathematical models; OSCILLATIONS; Physics; RED SHIFT; Sciences of the Universe; Sky surveys (astronomy); Texts; THREE-DIMENSIONAL CALCULATIONS
• ISSN: 1475-7516; 1475-7508; 1475-7516
• DOI: 10.1088/1475-7516/2013/04/026

We use the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) to detect and measure the position of the Baryonic Acoustic Oscillation (BAO) feature in the three-dimensional correlation function in the Lyman-a forest flux fluctuations at a redshift Z sub(eff) = 2.4. The feature is clearly detected at significance between 3 and 5 sigma (depending on the broadband model and method of error covariance matrix estimation) and is consistent with predictions of the standard ACDM model. We assess the biases in our method, stability of the error covariance matrix and possible systematic effects. We fit the resulting correlation function with several models that decouple the broadband and acoustic scale information. For an isotropic dilation factor, we measure (ProQuest: Formulae and/or non-USASCII text omitted) (stat.) + or -1 (syst.) (multiple statistical errors denote 1,2 and 3 sigma confidence limits) with respect to the acoustic scale in the fiducial cosmological model (flat ACDM with [Omega] sub(m) = 0.27, h = 0.7). When fitting separately for the radial and transversal dilation factors we find marginalised constraints (ProQuest: Formulae and/or non-USASCII text omitted) (stat.) + or -2.0 (syst.) and 100 x ( alpha - 1) = (ProQuest: Formulae and/or non-USASCII text omitted) (stat.) + or -3.0 (syst.). The dilation factor measurements arc significantly correlated with cross-correlation coefficient of ~ -0.55. Errors become significantly non-Gaussian for deviations over 3 standard deviations from best fit value. Because of the data cuts and analysis method, these measurements give tighter constraints than a previous BAO analysis of the BOSS DR9 Lyman- alpha forest sample, providing an important consistency test, of the standard cosmological model in a new redshift regime.