Related papers: A cosmological test with compact radio sources
Measurements of the polarization angle and orientation of cosmological radio sources may be used to search for unusual effects in the propagation of light through the universe. Recently, Nodland and Ralston (astro-ph/9704196) have claimed…
Powerful extended radio galaxies like Cygnus A can be used for cosmological tests. The characteristic, time-independent length $D_*$ for several radio sources is calculated and compared to the average physical length for a sample of radio…
In principle the geometry of the universe can be investigated by measuring the angular size of known objects as a function of distance. Thus the distribution of angular sizes provides a critical test of the stable and static model of the…
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…
There are many different approaches to using observations to constrain or determine the global cosmological parameters that describe our universe. Methods that rely upon a determination of the coordinate distance to high-redshift sources…
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…
The Hubble constant ($H_{0}$) is a measurement to describe the expansion rate of the Universe in the current era. However, there is a $4.4\sigma$ discrepancy between the measurements from the early Universe and the late Universe. In this…
The lensing effect of a cosmic string is studied, and some new methods are proposed to detect the cosmic string. The technique for using jets as extended gravitational lensing probes was firstly explored by Kronberg. We use the…
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…
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…
We present a general method for testing gamma-ray burst (GRB) jet structure and carry out a comprehensive analysis about the prevalent jet structure models. According to the jet angular energy distribution, we can not only derive the…
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…
A sample of radio-loud active galactic nuclei (AGN) at 2cm is studied to test the isotropic distribution of radio sources in the sky and their uniform distribution in space. The sample is complete flux-density limits of 1.5Jy for positive…
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…
In this Letter we explore a version of the test of cosmological geometry proposed by Alcock and Paczynski (1979), using observations of the Lyman-alpha forest in the spectra of close quasar pairs. By comparing the correlations in absorption…
Baldwin (1982) wrote that \emph{the distribution of sources in the radio luminosity, $P$, overall physical size, $D$, diagram} could be considered as \emph{the radio astronomer's $H-R$ diagram}. However, unlike the case of stars, not only…
During close angular approaches of solar system planets to astrometric radio sources, the apparent positions of these sources shift due to relativistic effects and, thus, these events may be used for testing the theory of general…
We suggest to use the observationally measured and theoretically justified correlation between size and rotational velocity of galactic discs as a viable method to select a set of high redshift standard rods which may be used to explore the…
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…
The lensing effect of curved space, which can cause the angular diameter of a fixed reference length seen on the sky to reach a minimum and then increase with redshift, depends sensitively on the value of the cosmological constant,…