2011/04/30 by Anže Slosar, Andreu Font-Ribera, Matthew M. Pieri +47 · 3 citations
Physics and Astronomy · #Astrophysics #Baryon #Baryon acoustic oscillations #Cosmology and Gravitation Theories #Dark matter #Distortion (music) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Lyman limit #Lyman-alpha forest #Physics #Quasar #Radio Astronomy Observations and Technology #Redshift #astro-ph.CO
paper · pdf · doi:10.1088/1475-7516/2011/09/001
many pages and figures; to be submitted to JCAP; v2: expanded section on instrument and primary reduction; minor clarifications, references; added author; matches version accepted by JCAP
arxiv created 2011/08/01 · openalex publication_date 2011/09/01 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 −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.