相关论文: Absence of a Periodic Component in Quasar z-Distri…

Discrete Fourier analysis on the quasar number count, as a function of redshift, $z$, calculated from the Sloan Digital Sky Survey DR6 release appears to indicate that quasars have preferred periodic redshifts with redshift intervals of…

A crucial test of any cosmological model is the distribution of distant objects such as quasars. Because of well defined selection criteria quasars found by a ultraviolet excess (UVX) survey are ideal candidates for testing the model out to…

With the recent observational evidence in extra galactic astronomy, the interpretation of the nature of quasar redshift continues to be a research interest. Very high redshifts are being detected for extragalactic objects that are…

We make an analysis of the distribution of the extensive Doppler redshift defined as $\widetilde{z}_{Dopp}=(z_{abs}-z_{em})/(1+z_{em})$ with a sample of 1317 absorption redshifts available from 401 quasars. The analysis reveals a bi-peak…

After estimating and removing all ejection-related Doppler components from the redshifts of the QSOs near NGC 1068, the remaining redshift is assumed to be intrinsic. This well-studied case is the first example in which it has finally been…

Recent observational evidence in extra galactic astronomy, the interpretation of the nature of quasar redshift continues to be research interest. Spectrum observation of high redshift quasar is young in nature. Observational evidence…

We have obtained complete redshift information for a sample of 442 radio-loud quasars with flux densities S(11cm) >= 0.25Jy. These come from a completely-identified sample of 878 flat-spectrum radio sources, so there is no optical magnitude…

Two new samples of QSOs have been constructed from recent surveys to test the hypothesis that the redshift distribution of bright QSOs is periodic in $\log(1+z)$. The first of these comprises 57 different redshifts among all known close…

We test the periodicity of quasar redshifts in the 2dF and SDSS surveys. In the overall surveys redshift peaks are already apparent in the brighter quasars. But by analyzing sample areas in detail it is shown that the redshifts fit very…

We have used the publicly available data from the 2dF Galaxy Redshift Survey and the 2dF QSO Redshift Survey to test the hypothesis that there is a periodicity in the redshift distribution of quasi-stellar objects (QSOs) found projected…

The distribution of SDSS quasars is described. The dependence of observational number of quasars within distances to an observer less than r on distance r is found to be the power law with correlation dimension value equal 2,71 in redshift…

We present a sample of 8498 quasars with both SDSS $ugriz$ optical and UKIDSS $YJHK$ near-IR photometric data. With this sample, we obtain the median colour-z relations based on 7400 quasars with magnitude uncertainties less than 0.1mag in…

A fundamental prediction of relativistic cosmologies is that, due to the expansion of space, observations of the distant cosmos should be time dilated and appear to run slower than events in the local universe. Whilst observations of…

The large observed redshift of quasars has suggested large cosmological distances and a corresponding enormous energy output to explain the brightness or luminosity as seen at earth. Alternative or complementary sources of redshift have not…

A systematic investigation of the relationship between different redshift estimation schemes for more than 91000 quasars in the Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6) is presented. The publicly available SDSS quasar redshifts…

It is commonly accepted that quasar redshifts have a cosmological character and that most of the quasars are at Gigaparsec distances. However, there are some cases where several quasars with completely different redshifts and a nearby…

We carry out a statistical analysis of the spatial distribution of galaxies at cosmological redshifts $0.16 \leq z \leq 0.47$ based on the SDSS\ DR12\ LOWZ catalogue. Our aim is to search and study possible large-scale quasi-regular…

We examine rest-frame ultraviolet spectra of 70 high redshift quasars (z>3.5) to study the chemical enrichment history of the gas closely related to the quasars, and thereby estimate the epoch of first star formation. The fluxes of several…

We report the investigation of spatial distribution of quasars using two different methods: the statistical study by means of 2-point correlation function and direct search for structures such as previously reported Large Quasar Groups.…

We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filter system and the quality of the SDSS imaging data are sufficient for determining accurate and precise photometric redshifts (``photo-z''s) of quasars. Using a sample…