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Title: Off-center observers versus supernovae in inhomogeneous pressure universes

Exact luminosity distance and apparent magnitude formulae are applied to the Union2 557 supernovae sample in order to constrain the possible position of an observer outside of the center of symmetry in spherically symmetric inhomogeneous pressure Stephani universes, which are complementary to inhomogeneous density Lemaître-Tolman-Bondi (LTB) void models. Two specific models are investigated. The first allows a barotropic equation of state at the center of symmetry without the need to specify a scale factor function (model IIA). The second has no barotropic equation of state at the center, but has an explicit dust-like scale factor evolution (model IIB). It is shown that even at 3σ CL, an off-center observer cannot be further than about 4.4 Gpc away from the center of symmetry, which is comparable to the reported size of a void in LTB models with the most likely value of the distance from the center at about 341 Mpc for model IIA and 68 Mpc for model IIB. The off-center observer cannot be farther away from the center than about 577 Mpc for model IIB at 3σ CL. It is determined that the best-fit parameters which characterize inhomogeneity are Ω{sub inh} = 0.77 (dimensionless: model IIA) and α =more » 7.31 × 10{sup –9} (s km{sup –1}){sup 2/3} Mpc{sup –4/3} (model IIB).« less
Authors:
; ;  [1]
  1. Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin (Poland)
Publication Date:
OSTI Identifier:
22365137
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; EQUATIONS OF STATE; LUMINOSITY; SPHERICAL CONFIGURATION; STAR EVOLUTION; SUPERNOVAE; SYMMETRY; UNIVERSE