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VLBI measurements of the sizes of compact extragalactic radio sources, jetted active galactic nuclei, provide data for probing the angular size--redshift relation, offering a complementary test to other distance--redshift methods. We…

In this paper the next attempt is made to clarify the nature of the Euclidean behavior of the boundary in the angular size-redshift cosmological test. It is shown experimentally that this can be explained by the selection determined by…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-13 V. R. Amirkhanyan

We discuss the ``angular size - redshift'' relation for compact radio sources distributed over a wide range of redshifts 0.01 < z < 4.73. Our study is based on a sample of 330 5 GHz VLBI contour maps taken from the literature. Unlike…

Astrophysics · Physics 2007-05-23 L. I. Gurvits , K. I. Kellermann , S. Frey

In this paper, based on a 2.29 GHz VLBI all-sky survey of 613 milliarcsecond ultra-compact radio sources with $0.0035<z<3.787$, we describe a method of identifying the sub-sample which can serve as individual standard rulers in cosmology.…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-08 Shuo Cao , Marek Biesiada , John Jackson , Xiaogang Zheng , Yuhang Zhao , Zong-Hong Zhu

By modifying the Chen and Wu ansatz, we have investigated some Friedmann models in which $\Lambda$ varies as $\rho$. In order to test the consistency of the models with observations, we study the angular size - redshift relation for 256…

General Relativity and Quantum Cosmology · Physics 2009-10-31 R. G. Vishwakarma

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…

Astrophysics · Physics 2009-11-07 J. A. S. Lima , J. S. Alcaniz

A linear evolution of the cosmological scale factor is a feature in several models designed to solve the cosmological constant problem via a coupling between scalar or tensor classical fields to the space-time curvature as well as in some…

Astrophysics · Physics 2009-11-07 Deepak Jain , Abha Dev , J. S. Alcaniz

We have re-examined an ancient VLBI survey of ultra-comact radio sources at 2.29 GHz, which gave fringe amplitudes for 917 such objects with total flux density >0.5 Jy approximately. A number of cosmological investigations based upon this…

Astrophysics · Physics 2009-11-11 J C Jackson , A L Jannetta

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 Omega_m=0.2 and…

Astrophysics · Physics 2009-11-10 J. C. Jackson

At bright radio powers ($P_{\rm 1.4 GHz} > 10^{25}$ W/Hz) the space density of the most powerful sources peaks at higher redshift than that of their weaker counterparts. This paper establishes whether this luminosity-dependent evolution…

Astrophysics of Galaxies · Physics 2015-09-16 E. E. Rigby , J. Argyle , P. N. Best , D. Rosario , H. J. A. Röttgering

The recent proposal by Kellermann (1993) to use the angular size/redshift relation of compact radio sources to obtain information on the value of cosmological parameters has provoked considerable discussion in the astronomical community. I…

Astrophysics · Physics 2011-05-23 R. Kayser

In this paper, we present a new compiled milliarcsecond compact radio data set of 120 intermediate-luminosity quasars in the redshift range $0.46< z <2.76$. These quasars show negligible dependence on redshifts and intrinsic luminosity, and…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-02 Shuo Cao , Xiaogang Zheng , Marek Biesiada , Jingzhao Qi , Yun Chen , Zong-Hong Zhu

We investigate the linear radio size properties of the $\mu$Jy populations of radio-selected active galactic nuclei (AGN) and star-forming galaxies (SFGs) using a multi-resolution catalog based on the original VLA-COSMOS 3\,GHz 0\farcs75…

We present a study of the trends in luminosity, linear size, spectral index, and redshift of classical double radio sources from three complete samples selected at successively fainter low radio-frequency flux-limits. We have been able to…

Astrophysics · Physics 2010-04-06 Katherine M. Blundell , Steve Rawlings , Chris J. Willott

Recent investigations of how the median size of extragalactic radio sources change with redshift have produced inconsistent results. Eales compared the radio and optical properties of a bright 3C and faint 6C sample and concluded that…

This study is devoted to the cosmological "angular size - redshift" test. An analysis is performed of the angular and linear sizes of galaxies from the new ASTRODEEP-JWST catalogue, which contains over 500,000 objects at high redshifts (up…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-05 A. A. Raikov , V. V. Tsymbal , N. Yu. Lovyagin

The redshifts of faint radio galaxies identified with giant radio source candidates selected from the sample of Machalski et al. (2001) have been measured. Given the redshift, the projected linear size and radio luminosity are then…

We calculate the expected number of strongly lensed radio sources in a sample of 6500 sources observed with the Very Large Array as part of the Cosmic Lens All Sky Survey (CLASS) during the first two sessions of its observations. A…

Astrophysics · Physics 2011-05-23 Asantha R. Cooray

In this paper, we use multi-frequency angular size measurements of 58 intermediate-luminosity quasars reaching the redshifts $z\sim 3$ and demonstrate that they can be used as standard rulers for cosmological inference. Our results indicate…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-17 Shuo Cao , Marek Biesiada , Jingzhao Qi , Yu Pan , Xiaogang Zheng , Tengpeng Xu , Xuan Ji , Zong-Hong Zhu

A sample of 20 powerful extended radio galaxies with redshifts between zero and two were used to determine constraints on global cosmological parameters. Data for six radio sources were obtained from the VLA archive, analyzed, and combined…

Astrophysics · Physics 2009-10-31 E. J. Guerra , Ruth A. Daly , Lin Wan
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