ar X iv : a st ro - p h / 05 06 44 9 v 4 1 9 Ju n 20 06 Can a dust dominated universe have accelerated expansion ?

ar X iv : a st ro - p h / 05 06 44 9 v 3 9 J un 2 00 6 Can a dust dominated universe have accelerated expansion ?

Recently, there has been suggestions that the apparent accelerated expansion of the universe is due not to a cosmological constant, but rather to inhomogeneities in the distribution of matter. In this work, we investigate a specific class of inhomogeneous models that can be solved analytically, namely the dust-dominated Lemâitre-Tolman-Bondi universe models. We show that they do not permit acce...

ar X iv : a st ro - p h / 03 06 45 9 v 1 2 3 Ju n 20 03 Extinction by grey dust in the intergalactic medium

Condensation in the outer regions of decaying supernovae is an efficient source of dust with grain size up to more than 1µm. The largest grains leave the parent galaxy, thus forming " grey " intergalactic dust, which can explain the observed dimming of light from distant supernovae without invoking cosmic acceleration.

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ar X iv : a st ro - p h / 05 06 40 4 v 1 1 7 Ju n 20 05 The Ω DE − Ω M Plane in Dark Energy Cosmology

The dark energy cosmology with the equation of state w = constant is considered in this paper. The ΩDE−ΩM plane has been used to study the present state and expansion history of the universe. Through the mathematical analysis, we give the theoretical constraint of cosmological parameters. Together with some observations such as the transition redshift from deceleration to acceleration, more pre...

ar X iv : a st ro - p h / 99 06 46 3 v 3 1 4 Ju l 1 99 9 The Cosmic Triangle : Assessing the State of the Universe

The cosmic triangle is introduced as a way of representing the past, present, and future status of the universe. Our current location within the cosmic triangle is determined by the answers to three questions: How much matter is in the universe? Is the expansion rate slowing down or speeding up? And, is the universe flat? A review of recent observations suggests a universe that is lightweight (...