and Cosmology

8. Cosmology III: The Cosmological Parameters
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Fig. 8.32. 1σ and 2σ confidence regions (dark gray and light
gray areas, respectively) in the Ω m –Ω Λ plane. In the upper
left panel, only the WMAP data were used. In the upper right
panel, the WMAP data were combined with CMB measurements
on smaller angular scales (WMAPext). In the lower
left panel, the WMAPext data were combined with the determination
of the Hubble constant from the HST Key Project,
and the confidence region which is obtained from SN Ia measurements
is included only for comparison. In the lower right
panel, the SN Ia data are included in addition. The dashed line
indicates models of vanishing curvature, Ω m + Ω Λ = 1
Table 8.1. The six basic parameters determined from the
WMAP data, where a flat cosmological model (Ω m +Ω Λ = 1)
is assumed. A is the amplitude and n s the slope of the primordial
power spectrum, and τ is the optical depth with respect
to Thomson scattering after reionization. χeff 2 /ν is a statistical
measure for the agreement of the best-fit model and the data.
The different columns list the best-fit parameters obtained by
using the WMAP data alone, WMAP in combination with
CMB measurements on small angular scales (WMAPext),
WMAPext with additional inclusion of the power spectrum
from the 2dFGRS (WMAPext+2dFGRS), and finally the additional
inclusion of the power spectrum from the Lyα forest
(WMAPext+2dFGRS+Lyα) (from Spergel et al., 2003, ApJS,
148, 175)
WMAP WMAPext WMAPext+2dFGRS WMAPext+2dFGRS+Lyα
A 0.9 ± 0.1 0.8 ± 0.1 0.8 ± 0.1 0.75 +0.08
−0.07
n 0.99 ± 0.04 0.97 ± 0.03 0.97 ± 0.03 0.96 ± 0.02
τ 0.166 −0.071 +0.076
0.143 +0.071
−0.062 0.148 +0.073
−0.071 0.117 +0.057
−0.053
h 0.72 ± 0.05 0.73 ± 0.05 0.73 ± 0.03 0.72 ± 0.03
Ω m h 2 0.14 ± 0.02 0.13 ± 0.01 0.134 ± 0.006 0.133 ± 0.006
Ω b h 2 0.024 ± 0.001 0.023 ± 0.001 0.023 ± 0.001 0.0226 ± 0.0008
χeff 2 /ν 1429/1341 1440/1352 1468/1381 ...