Cosmological parameter analysis including SDSS Ly forest and galaxy bias: Constraints on the primordial spectrum of fluctuations, neutrino mass, and dark energy

Uroš Seljak, Alexey Makarov, Patrick McDonald, Scott F. Anderson, Neta A. Bahcall, J. Brinkmann, Scott Burles, Renyue Cen, Mamoru Doi, James E. Gunn, Željko Ivezić, Stephen Kent, Jon Loveday, Robert H. Lupton, Jeffrey A. Munn, Robert C. Nichol, Jeremiah P. Ostriker, David J. Schlegel, Donald P. Schneider, Max TegmarkDaniel E. Vanden Berk, David H. Weinberg, Donald G. York

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We combine the constraints from the recent Lya forest analysis of the Sloan Digital Sky Survey (SDSS) and the SDSS galaxy bias analysis with previous constraints from SDSS galaxy clustering, the latest supernovae, and 1st year WMAP cosmic microwave background anisotropies. We find significant improvements on all of the cosmological parameters compared to previous constraints, which highlights the importance of combining Lya forest constraints with other probes. Combining WMAP and the Lya forest we find for the primordial slope ns=0.98±0.02. We see no evidence of running, dn/dln?k=-0.003±0. 010, a factor of 3 improvement over previous constraints. We also find no evidence of tensors, r<0.36 (95% c.l.). Inflationary models predict the absence of running and many among them satisfy these constraints, particularly negative curvature models such as those based on spontaneous symmetry breaking. A positive correlation between tensors and primordial slope disfavors chaotic inflation-type models with steep slopes: while the V??2 model is within the 2-sigma contour, V??4 is outside the 3-sigma contour. For the amplitude we find s8=0.90±0.03 from the Lya forest and WMAP alone. We find no evidence of neutrino mass: for the case of 3 massive neutrino families with an inflationary prior, ?m?<0.42 eV and the mass of lightest neutrino is m1<0.13 eV at 95% c.l. For the 3 massless +1 massive neutrino case we find m?<0.79 eV for the massive neutrino, excluding at 95% c.l. all neutrino mass solutions compatible with the LSND results. We explore dark energy constraints in models with a fairly general time dependence of dark energy equation of state, finding O?=0.72±0.02, w(z=0.3)=-0.98-0.12+0.10, the latter changing to w(z=0.3)=-0.92-0.10+0.09 if tensors are allowed. We find no evidence for variation of the equation of state with redshift, w(z=1)=-1.03-0.28+0.21. These results rely on the current understanding of the Lya forest and other probes, which need to be explored further both observationally and theoretically, but extensive tests reveal no evidence of inconsistency among different data sets used here.

Original languageEnglish (US)
Article number103515
Pages (from-to)1-20
Number of pages20
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number10
StatePublished - May 15 2005

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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