The Lyman-α forest in three dimensions: measurements of large scale flux correlations from BOSS 1st-year data
- Brookhaven National Laboratory, Blgd 510, Upton NY 11375 (United States)
- Institut de Ciències de l'Espai (CSIC-IEEC), Campus UAB, Fac. Ciències, torre C5 parell 2, Bellaterra, Catalonia (Spain)
- Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, Colorado 80309 (United States)
- CEA, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette (France)
- APC, Université Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rue A. Domon and L. Duquet, Paris (France)
- Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States)
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
- Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA 15213 (United States)
- University of Utah, Dept. of Physics and Astronomy, 115 S 1400 E, Salt Lake City, UT 84112 (United States)
- Harvard College Observatory, 60 Garden St., Cambridge MA 02138 (United States)
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)
- 104-20 Queens Blvd 17A, Forest Hills, NY 11375 (United States)
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{sup −τ}) is securely detected out to comoving separations of 60 h{sup −1}Mpc, 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.
- OSTI ID:
- 22277819
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2011, Issue 09; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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