TY - JOUR
T1 - The linear theory power spectrum from the Lyα forest in the sloan digital sky survey
AU - McDonald, Patrick
AU - Seljak, Uroš
AU - Cen, Renyue
AU - Shih, David
AU - Weinberg, David H.
AU - Burles, Scott
AU - Schneider, Donald P.
AU - Schlegel, David J.
AU - Bahcall, Neta A.
AU - Briggs, John W.
AU - Brinkmann, J.
AU - Fukugita, Masataka
AU - Ivezić, Željko
AU - Kent, Stephen
AU - Vanden Berk, Daniel E.
PY - 2005/12/20
Y1 - 2005/12/20
N2 - We analyze the SDSS Lyα forest PF(k, z) measurement to determine the linear theory power spectrum. Our analysis is based on fully hydrodynamic simulations, extended using hydro-particle-mesh simulations. We account for the effect of absorbers with damping wings, which leads to an increase in the slope of the linear power spectrum. We break the degeneracy between the mean level of absorption and the linear power spectrum without significant use of external constraints. We infer linear theory power spectrum amplitude ΔL2(kL = 0.009 s km -1, zp = 3.0) = 0.452-0.057 - 0.116+0.069 +0.141 and slope neff(kp, zp) = -2.321-0.047 - 0.102+0.055 +0.131 (possible systematic errors are included through nuisance parameters in the fit: a factor ≳5 smaller errors would be obtained on both parameters if we ignored modeling uncertainties). The errors are correlated and not perfectly Gaussian, so we provide a χ2 table to accurately describe the results. The result corresponds to σ8 = 0.85, n = 0.94 for a ΛCDM model with Ωm = 0.3, Ωb = 0.04, and h = 0.7 but is most useful in a combined fit with the CMB. The inferred curvature of the linear power spectrum and the evolution of its amplitude and slope with redshift are consistent with expectations for ΛCDM models, with the evolution of the slope, in particular, being tightly constrained. We use this information to constrain systematic contamination, e.g., fluctuations in the UV background. This paper should serve as a starting point for more work to refine the analysis, including technical improvements such as increasing the size and number of the hydrodynamic simulations and improvements in the treatment of the various forms of feedback from galaxies and quasars.
AB - We analyze the SDSS Lyα forest PF(k, z) measurement to determine the linear theory power spectrum. Our analysis is based on fully hydrodynamic simulations, extended using hydro-particle-mesh simulations. We account for the effect of absorbers with damping wings, which leads to an increase in the slope of the linear power spectrum. We break the degeneracy between the mean level of absorption and the linear power spectrum without significant use of external constraints. We infer linear theory power spectrum amplitude ΔL2(kL = 0.009 s km -1, zp = 3.0) = 0.452-0.057 - 0.116+0.069 +0.141 and slope neff(kp, zp) = -2.321-0.047 - 0.102+0.055 +0.131 (possible systematic errors are included through nuisance parameters in the fit: a factor ≳5 smaller errors would be obtained on both parameters if we ignored modeling uncertainties). The errors are correlated and not perfectly Gaussian, so we provide a χ2 table to accurately describe the results. The result corresponds to σ8 = 0.85, n = 0.94 for a ΛCDM model with Ωm = 0.3, Ωb = 0.04, and h = 0.7 but is most useful in a combined fit with the CMB. The inferred curvature of the linear power spectrum and the evolution of its amplitude and slope with redshift are consistent with expectations for ΛCDM models, with the evolution of the slope, in particular, being tightly constrained. We use this information to constrain systematic contamination, e.g., fluctuations in the UV background. This paper should serve as a starting point for more work to refine the analysis, including technical improvements such as increasing the size and number of the hydrodynamic simulations and improvements in the treatment of the various forms of feedback from galaxies and quasars.
KW - Cosmology: theory
KW - Intergalactic medium
KW - Large-scale structure of universe quasars: absorption lines
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U2 - 10.1086/497563
DO - 10.1086/497563
M3 - Article
AN - SCOPUS:30644458315
SN - 0004-637X
VL - 635
SP - 761
EP - 783
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2 I
ER -