Deceleration without dark matter

Jackson, John and Dodgson, Marina (1997) Deceleration without dark matter. Monthly Notices of the Royal Astronomical Society, 285 (4). pp. 806-810. ISSN 0035-8711

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Abstract

In homogeneous isotropic cosmological models the angular size θ of a standard measuring rod changes with redshift z in a manner that depends upon the parameters of the model. It has been argued that as a population ultracompact (milliarcsecond) radio sources measured by very long-baseline interferometry (VLBI) do not evolve with cosmic epoch, and thus comprise a set of standard objects, at least in a statistical sense. Here we examine the angular-size/redshift relation for 256 ultracompact sources with z in the range 0.5 to 3.8 for cosmological models with two degrees of freedom (Ω 0 and Λ 0). The canonical inflationary cold dark matter model (Λ 0 = 1, Λ 0 = 0) appears to be ruled out by the observed relationship, whereas low-density models with a cosmological constant of either sign are favoured.

Item Type:	Article
Uncontrolled Keywords:	Cosmology: observations; Cosmology: theory; Dark matter
Subjects:	F500 Astronomy G300 Statistics
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Becky Skoyles
Date Deposited:	27 Jan 2015 16:36
Last Modified:	13 Oct 2019 00:22
URI:	http://nrl.northumbria.ac.uk/id/eprint/20261

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