Apparent versus true value of the cosmological constant

Abstract

Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the universe can be accurately described by a homogeneous model. Even in the presence of a cosmological constant we cannot exclude nevertheless the presence of a small local inhomogeneity which could affect the apparent value of the cosmological constant. Neglecting the presence of the inhomogeneity can in fact introduce a systematic misinterpretation of cosmological data, leading to the distinction between an apparent and the true value of the cosmological constant. But is such a difference distinguishable? Recently we set out to model the local inhomogeneity with a ΛLTB solution and computed the relation between the apparent and the true value of the cosmological constant. In this essay we reproduce the essence of our model with the emphasis on its physical implications.

Some parts need to be revised

References in corpus (21)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• Type Ia Supernova Discoveries at z>1 From the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution
• Cosmological Results from High-z Supernovae
• New Constraints on ${\Omega }_M$, ${\Omega }_{\Lambda }$, and w from an Independent Set of Eleven High-Redshift Supernovae Observed with HST
• 23 High Redshift Supernovae from the IfA Deep Survey: Doubling the SN Sample at z>0.7
• An inhomogeneous alternative to dark energy?
• Can the Acceleration of Our Universe Be Explained by the Effects of Inhomogeneities?
• Do we really see a cosmological constant in the supernovae data ?
• Time drift of cosmological redshifts as a test of the Copernican principle
• Large Scale Inhomogeneity Versus Source Evolution -- Can We Distinguish Them Observationally?
• Living in a Void: Testing the Copernican Principle with Distant Supernovae
• Mapping Luminosity-Redshift Relationship to LTB Cosmology
• Can inhomogeneties accelerate the cosmic volume expansion?
• Distinguishing Between Void Models and Dark Energy with Cosmic Parallax and Redshift Drift
• Solving the Inverse Problem with Inhomogeneous Universes
• LTB universes as alternatives to dark energy: does positive averaged acceleration imply positive cosmic acceleration?
• Cosmic Parallax as a probe of late time anisotropic expansion
• Mimicking the cosmological constant for more than one observable with large scale inhomogeneities
• Redshift spherical shell energy in isotropic Universes

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