Related papers: A study of the angular size-redshift relation for …
The shape of the primordial fluctuation spectrum is probed by cosmic microwave background fluctuations which measure density fluctuations at z~1000 on scales of hundreds of Mpc and from galaxy redshift surveys, which measure structure at…
We have formed a complete sample of 26 low redshift (z < 0.3) giant radio galaxies (GRGs) from the WENSS survey, selected at flux densities above 1 Jy at 325 MHz. We present 10.5-GHz observations with the 100-m Effelsberg telescope of 18…
We use updated Hubble parameter and baryon acoustic oscillation data, as well as other lower-redshift Type Ia supernova, Mg II reverberation-measured quasar, quasar angular size, H II starburst galaxy, and Amati-correlated gamma-ray burst…
We have carried out optical spectroscopy with the Anglo-Australian Telescope for 24,726 objects surrounding a sample of 19 Giant Radio Galaxies (GRGs) selected to have redshifts in the range 0.05 to 0.15 and projected linear sizes from 0.8…
The luminosity distance vs. redshift law is now measured using supernovae and gamma ray bursts, and the angular size distance is measured at the surface of last scattering by the CMB and at z = 0.35 by baryon acoustic oscillations. In this…
We have optically identified a sample of 56 featureless continuum objects without significant proper motion from the 2dF QSO Redshift Survey (2QZ). The steep number--magnitude relation of the sample, $n(\bj) \propto 10^{0.7\bj}$, is similar…
Observations of the redshifted 21-cm signal (in absorption or emission) allow us to peek into the epoch of "dark ages" and the onset of reionization. These data can provide a novel way to learn about the nature of dark matter, in particular…
We present the results of a z>2.9 survey for HI 21-cm and molecular absorption in the hosts of radio quasars using the GMRT and the Tidbinbilla 70-m telescope. Previously published searches, which are overwhelmingly at redshifts of z<1,…
The time evolution of `fiducial' radio sources derived from fitting the dynamical model of Kaiser et al. (1997) is compared with the observational data for the `clan' sources found in the sample of giant and normal-size FRII-type sources…
We use the observed polarisation properties of a sample of 26 powerful radio galaxies and radio-loud quasars to constrain the conditions in the Faraday screens local to the sources. We adopt the cosmological redshift, low-frequency radio…
Systems where multiple sources at different redshifts are strongly lensed by the same deflector allow one to directly investigate the evolution of the angular diameter distances with redshift, and thus to learn about the geometry of the…
(Abridged) This is the second in a series of three papers which present and interpret basic observational data on the 6C* 151-MHz radio sample: a low-frequency selected sample which exploits filtering criteria based on radio properties…
The low-redshift evolution of the intergalactic medium is investigated using hydrodynamic cosmological simulations. The assumed cosmological model is a critical density cold dark matter universe. The imposed uniform background of ionizing…
Observational constraints guide one forcefully to examine models in which the matter density is substantially less than critical density. Particularly noteworthy are those which are consistent with inflation. For these models, microwave…
Distance-redshift data can impose strong constraints on dark energy models even when the equation of state is oscillatory. Despite the double integral dependence of the distance on the equation of state, precision measurement of the…
Observations of gamma-ray bursts up to $z\sim 9$ are best suited to study the possible evolution of the Universe equation of state at intermediate redshifts. We apply the Combo-relation to a sample of 174 gamma ray bursts to investigate…
The growth rate of matter density perturbations has been measured from redshift-space distortion (RSD) in the galaxy power spectrum. We constrain the model parameter space for representative modified gravity models to explain the dark…
We use 12 large quasar group (LQG) samples to investigate the homogeneity of $0.5\lesssim z \lesssim 2$ Universe ($z$ denotes the redshift). We calculate the bias factor $b$ and the two-point correlation function $\xi_{{\rm LQG}}$ for such…
The concordance (LambdaCDM) model reproduces the main current cosmological observations assuming the validity of general relativity at all scales and epochs, the presence of cold dark matter, and of a cosmological constant, equivalent to a…
We study the expansion history of the universe up to a redshift of z=1.75 using the 194 recently published SnIa data by Tonry et. al. and Barris et. al. In particular we find the best fit forms of several cosmological models and $H(z)$…