COBE-DMR--normalized Open Cold Dark Matter Cosmogonies
Abstract
Cut-sky orthogonal mode analyses of the COBE-DMR 53 and 90 GHz sky maps are used to determine the normalization of a variety of open cosmogonical models based on the cold dark matter scenario. To constrain the allowed cosmological parameter range for these open cosmogonies, the predictions of the DMR-normalized models are compared to various observational measures of cosmography and large-scale structure, viz., the age of the universe; small-scale dynamical estimates of the clustered-mass density parameter Ω0 constraints on the Hubble parameter h, the X-ray cluster baryonic-mass fraction ΩB/Ω0, and the matter power spectrum shape parameter; estimates of the mass perturbation amplitude; and constraints on the large-scale peculiar velocity field.
The open-bubble inflation model (Ratra & Peebles; Bucher, Goldhaber, & Turok; Yamamoto, Sasaki, & Tanaka) is consistent with current determinations of the 95% confidence level (c.l.) range of these observational constraints, provided 0.3 < Ω0 <~ 0.6 (~95% c.l.). More specifically, for a range of h, the model is reasonably consistent with recent high-redshift estimates of the deuterium abundance that suggest ΩBh2 ~ 0.007, provided Ω0 ~ 0.35; recent high-redshift estimates of the deuterium abundance that suggest ΩBh2 ~ 0.02 favor Ω0 ~ 0.5, while the old nucleosynthesis value ΩBh2 = 0.0125 requires Ω0 ~ 0.4. Small shifts in the inferred COBE-DMR normalization amplitudes due to (1) the small differences between the galactic- and ecliptic-coordinate sky maps, (2) the inclusion or exclusion of the quadrupole moment in the analysis, (3) the faint high-latitude Galactic emission treatment, and (4) the dependence of the theoretical cosmic microwave background anisotropy angular spectral shape on the value of h and ΩB are explicitly quantified. Corresponding variations in the likelihood fits of models to the DMR data then imply that the DMR data alone do not possess sufficient discriminative power to prefer any values for Ω0, h, or ΩB at the 95% c.l. for the models considered. At a lower c.l., and when the quadrupole moment is included in the analysis, the DMR data are most consistent with either Ω0 <~ 0.1 or Ω0 ~ 0.7 (depending on the model considered). However, when the quadrupole moment is excluded from the analysis, the DMR data are most consistent with Ω0 ~ 0.35-0.5 in all open models considered (with 0.1 <= Ω0 <= 1), including the open-bubble inflation model. Earlier claims (Yamamoto & Bunn; Bunn & White) that the DMR data require a 95% c.l. lower bound on Ω0 (~0.3) are not supported by our (complete) analysis of the 4 year data: the DMR data alone cannot be used to constrain Ω0 meaningfully.- Publication:
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The Astrophysical Journal Supplement Series
- Pub Date:
- January 1998
- DOI:
- 10.1086/313062
- arXiv:
- arXiv:astro-ph/9608054
- Bibcode:
- 1998ApJS..114....1G
- Keywords:
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- COSMOLOGY: COSMIC MICROWAVE BACKGROUND;
- COSMOLOGY: OBSERVATIONS;
- GALAXIES: FORMATION;
- COSMOLOGY: LARGE-SCALE STRUCTURE OF UNIVERSE;
- Cosmology: Cosmic Microwave Background;
- Cosmology: Observations;
- Galaxies: Formation;
- Cosmology: Large-Scale Structure of Universe;
- Astrophysics
- E-Print:
- 49 pages, uses aaspp4.sty