Open AccessConstraints on cosmological parameters from recent measurements of cosmic microwave background anisotropy
Author(s) -
S. Hancock,
G. Rocha,
A. Lasenby,
Carlos M. Gutiérrez
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01169.x
Subject(s) - physics , cosmic microwave background , astrophysics , big bang (financial markets) , hubble's law , big bang nucleosynthesis , age of the universe , universe , cosmological constant , inflation (cosmology) , cosmic background radiation , cosmology , cold dark matter , hubble volume , spectral density , astronomy , dark energy , anisotropy , de sitter universe , nucleosynthesis , theoretical physics , stars , quantum mechanics , statistics , mathematics , finance , economics
A key prediction of cosmological theories for the origin and evolution of structure in the Universe is the existence of a ‘Doppler peak’ in the angular power spectrum of cosmic microwave background (CMB) fluctuations. We present new results from a study of recent CMB observations which provide the first strong evidence for the existence of a ‘Doppler peak’ localized in both angular scale and amplitude. This first estimate of the angular position of the peak is used to place a new direct limit on the curvature of the Universe, corresponding to a density of Ω = 0.7 +0.8 −0.5 , consistent with a flat universe. Very low‐density ‘open’ universe models are inconsistent with this limit unless there is a significant contribution from a cosmological constant. For a flat standard cold dark matter dominated universe we use our results in conjunction with big bang nucleosynthesis constraints to determine the value of the Hubble constant as H 0 = 30 − 70 km s −1 Mpc −1 for baryon fractions Ω b = 0.05 to 0.2. For H 0 = 50 km s −1 Mpc −1 we find the primordial spectral index of the fluctuations to be n = 1.1 ± 0.1, in close agreement with the inflationary prediction of n ≃ 1.0.