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Journal of Cosmology and Astroparticle Physics 09 (2011) 001
The Lyman-α forest in three dimensions: measurements of large scale flux correlations from BOSS 1st-year data
Anže Slosar, Andreu Font-Ribera, Matthew M. Pieri, James Rich1, Jean-Marc Le Goff, E. Aubourg2, Jon Brinkmann, N.G. Busca2, Bill Carithers, Romain Charlassier, Marina Cortês, Rupert Croft, Kyle S. Dawson, Daniel Eisenstein, J.-C. Hamilton2, Shirley Ho, Khee-Gan Lee, Robert Lupton, Patrick McDonald, Bumbarija Medolin, Demitri Muna, Jordi Miralda-Escudé, Adam D. Myers, Robert C. Nichol, N. Palanque-Delabrouille1, I. Pâris3, Patrick Petitjean, Yodovina Piškur, E. Rollinde3, Nicholas P. Ross, David J. Schlegel, Donald P. Schneider, Erin Sheldon, Benjamin A. Weaver, David H. Weinberg, C. Yeche1, Donald G. York
(2011-09)

Using a sample of approximately 14,000 z > 2.1 quasars observed in the first year of the Baryon Oscillation Spectroscopic Survey (BOSS), we measure the three-dimensional correlation function of absorption in the Lyman-α forest. The angle-averaged correlation function of transmitted flux (F = e-τ) is securely detected out to comoving separations of 60 h-1Mpc, the first detection of flux correlations across widely separated sightlines. A quadrupole distortion of the redshift-space correlation function by peculiar velocities, the signature of the gravitational instability origin of structure in the Lyman-α forest, is also detected at high significance. We obtain a good fit to the data assuming linear theory redshift-space distortion and linear bias of the transmitted flux, relative to the matter fluctuations of a standard ΛCDM cosmological model (inflationary cold dark matter with a cosmological constant). At 95% confidence, we find a linear bias parameter 0.16 < b < 0.24 and redshift-distortion parameter 0.44 < β < 1.20, at central redshift z = 2.25, with a well constrained combination b(1+β) = 0.336±0.012. The errors on β are asymmetric, with β = 0 excluded at over 5σ confidence level. The value of β is somewhat low compared to theoretical predictions, and our tests on synthetic data suggest that it is depressed (relative to expectations for the Lyman-α forest alone) by the presence of high column density systems and metal line absorption. These results set the stage for cosmological parameter determinations from three-dimensional structure in the Lyman-α forest, including anticipated constraints on dark energy from baryon acoustic oscillations.
1:  IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
2:  APC - UMR 7164 - AstroParticule et Cosmologie
3:  IAP - Institut d'Astrophysique de Paris
APC - Cosmologie et gravitation
Physics/Astrophysics/Cosmology and Extra-Galactic Astrophysics

Sciences of the Universe/Astrophysics/Cosmology and Extra-Galactic Astrophysics
Fulltext link: 
http://fr.arXiv.org/abs/1104.5244