Testing the angular-size versus redshift relation with compact radio sources
نویسندگان
چکیده
منابع مشابه
Tight cosmological constraints from the angular-size/redshift relation for ultra-compact radio sources
Some years ago (Jackson and Dodgson 1997) analysis of the angular-size/redshift relationship for ultra-compact radio sources indicted that for spatially flat universes the best choice of cosmological parameters was Ωm = 0.2 and ΩΛ = 0.8. Here I present an astrophysical model of these sources, based upon the idea that for those with redshift z > 0.5 each measured angular size corresponds to a si...
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We discuss the “angular size – redshift” relation for compact radio sources distributed over a wide range of redshifts 0.011 ≤ z ≤ 4.72. Our study is based on a sample of 330 5 GHz VLBI contour maps taken from the literature. Unlike extended source samples, the “angular size – redshift” relation for compact radio sources appears consistent with the predictions of standard Friedmann world models...
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We use the Gurvits, Kellermann, & Frey compact radio source angular size versus redshift data to place constraints on cosmological model parameters in models with and without a constant or time-variable cosmological constant. The resulting constraints are consistent with but weaker than those determined using current supernova apparent magnitude versus redshift data. Subject headings: cosmology...
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The “Cardassian Expansion Scenario” was recently proposed by Freese & Lewis as an alternative to a cosmological constant in explaining the current accelerating universe. In this paper we investigate observational constraints on this scenario from recent measurements of the angular size of high-z compact radio sources compiled by Gurvits and coworkers. We show that the allowed intervals for n an...
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We investigate observational constraints on the cosmic equation of state from measurements of angular size for a large sample of milliarcsecond compact radio-sources. The results are based on a flat Friedmann-Robertson-Walker (FRW) type models driven by non-relativistic matter plus a smooth dark energy component parametrized by its equation of state p x = ωρ x (−1 ≤ ω < 0). The allowed interval...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1995
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/277.3.753