Deflationary cosmology: Constraints from angular size and ages of globular clusters

2002/02/28 by J. V. Cunha, J. S. Alcaniz, J. A. S. Lima · 23 citations
Physics and Astronomy · #Angular diameter #Astrophysics #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Globular cluster #Lambda #Mathematical physics #Omega #Physics #Quantum mechanics #Redshift #Stars #astro-ph

paper · pdf · doi:10.1103/physrevd.66.023520

published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 66(2) (American Physical Society) · 6 pages, 3 figures, revised version to appear in Phys. Rev. D

arxiv created 2002/07/02 · openalex publication_date 2002/07/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Observational constraints to a large class of decaying vacuum cosmologies are derived using the angular size data of compact radio sources and the latest age estimates of globular clusters. For this class of deflationary \ensuremathΛ(t) models, the present value of the vacuum energy density is quantified by a positive \ensuremathβ parameter smaller than unity. In the case of milliarcsecond compact radio-sources, we find that the allowed intervals for \ensuremathβ and the matter density parameter \ensuremathΩ_m are heavily dependent on the value of the mean projected linear size l. For l\ensuremath≃20h^\ensuremath-1\ensuremath-30h^\ensuremath-1 pc, the best fit occurs for \ensuremathβ\ensuremath∼0.58, \ensuremathΩ_m\ensuremath∼0.58, and \ensuremathβ\ensuremath∼0.76, \ensuremathΩ_m\ensuremath∼0.28, respectively. This analysis shows that if one minimizes \ensuremathχ² for the free parameters l, \ensuremathΩ_m and \ensuremathβ, the best fit for these angular size data corresponds to a decaying \ensuremathΛ(t) with \ensuremathΩ_m=0.54, \ensuremathβ=0.6, and l=22.64h^\ensuremath-1 pc. Constraints from age estimates of globular clusters and old high redshift galaxies are not so restrictive, thereby suggesting that there is no age crisis for this kind of \ensuremathΛ(t) cosmologies.

Citations

• Measurement of stellar age from uranium decay
• Measurements of Ω and Λ from 42 High‐Redshift Supernovae
• Dark Energy and the Epoch of Galaxy Formation
• Inflationary cosmology and thermodynamics
• Prospects for constraining cosmology with the extragalactic cosmic microwave background temperature
• Thermal Properties of an Inflationary Universe
• Evolution of the scale factor with a variable cosmological term
• Cosmological consequences of a rolling homogeneous scalar field
• Gravity on a brane in infinite-volume extra space
• Constraining the equation of state of the Universe from distant Type Ia supernovae and cosmic microwave background anisotropies
• The Case for a Positive Cosmological Lambda-term

Cited by

• Current and future supernova constraints on decayingΛcosmologies
• Clustering, angular size, and dark energy