Tangential large scale structure as a standard ruler: curvature parameters from quasars
Abstract
Several observational analyses suggest that matter is spatially structured at a scale of LLSS ≈ 130 h Mpc-1 at low redshifts. This peak in the power spectrum provides a standard ruler in comoving space} which can be used to compare the local geometry at high and low redshifts, thereby constraining the curvature parameters. It is shown here that this power spectrum peak is present in the observed quasar distribution at z~2: qualitatively, via wedge diagrams which clearly show a void-like structure, and quantitatively, via one-dimensional Fourier analysis of the quasars' tangential distribution. The sample studied here contains 812 quasars. The method produces strong constraints (68% confidence limits) on the density parameter Ω0 and weaker constraints on the cosmological constant λ0, which can be expressed by the relation Ω0 = (0.24 ± 0.15) + (0.10 ± 0.08) λ0 . Independently of λ0 (in the range λ0 \in [0,1]), the constraint is 0.1 < Ω0 < 0.45. Constraints if the cosmological constant is zero or if λ0 ≡ 1-Ω0 are Ω0= 0.24+0.05-0.15 and Ω0=0.30 ± 0.15 respectively. The power spectrum peak method is independent from the supernovae Type Ia method by choice of astrophysical object, by redshift range, and by use of a standard ruler instead of a standard candle. Combination of the two results yields Ω0 = (0.30±0.11) + (0.57±0.11) (λ0-0.7), 0.55 < λ0 < 0.95, (68% confidence limits) without assuming that λ0 ≡ 1-Ω0. This strongly supports the possibility that the observable universe satisfies a nearly flat, perturbed Friedmann-Lemaître-Robertson-Walker model, independently of any cosmic microwave background observations. In other words it has been shown that Ω0 + λ0 = (1.0 ± 0.11) + (1.57 ± 0.11) (λ0 - 0.7).
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 2000
- DOI:
- 10.48550/arXiv.astro-ph/9911413
- arXiv:
- arXiv:astro-ph/9911413
- Bibcode:
- 2000A&A...358..395R
- Keywords:
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- COSMOLOGY: OBSERVATIONS;
- COSMOLOGY: THEORY;
- GALAXIES: QUASARS: GENERAL;
- COSMOLOGY: DISTANCE SCALE;
- COSMOLOGY: LARGE-SCALE STRUCTURE OF UNIVERSE;
- REFERENCE SYSTEMS;
- Astrophysics
- E-Print:
- 15 pages, 15 figures