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An appreciable number of galaxies have been discovered in recent years which are assigned high redshifts. High redshift galaxies (HRGs) are used as cosmological tools for probing early universe and knowledge of star formation. However, literature search revealed some inconsistencies in identification of emission lines used for redshift determination in some of the HRGs. We re-examined the spectra of 15 HRGs, as examples, that are available in the published literature and show that the high values of redshift may have been assigned to these objects due to the misidentification of the observed lines. We demonstrate that the observed emission lines can be identified with alternative search lines at higher wavelengths which are blueshifted instead of the lines used for redshift measurements. Observed blueshifts can be interpreted in a model of multiple expanding universes.

The peak in the distribution of apparent magnitude (V) of QSOs at 18.0 can be explained by loss of QSOs forV<-18.0 arising out of selection effects due to the availability of search lines necessary for the determination of redshifts and due to the misidentification of QSOs as Main-Sequence stars. ForV>18.0, the number of objects seem to fall off as they become progressively fainter and detection efficiency goes down. The present analysis also shows that a strong correlation exists between apparent magnitude and redshift of QSOs indicating redshifts are of cosmological origin.

In this Letter we report the findings of a statistically significant relation between the continuum color indices and redshift of optically violent variable QSOs. No such correlation is found to exist for non-variable and moderately variable QSOs.

A gap in the distribution of a parameter is simply the absence of the parameter for the values corresponding to the gap. The gap in the emission line redshift (z) of QSOs thus represents absence of QSOs with emission line redshift values corresponding to the gap region. Gaps in emission line redshifts of QSOs have been analysed statistically with updated data consisting of 1549 values. The study indicates: (i) There is a critical redshiftzc=2.4, which separates two distinct phases in the creation of QSOs. Forz>zc, the creation appears to have been a slow process. Atz?zc there was a triggering action which produced a burst of QSOs simultaneously. Forzc, the rate of production of QSOs have been fast. (ii) The distribution of gaps atzc; appear to be consequence of periodicities, provided the periodicities involved are perfect and the redshift values are accurate. (iii) The distribution of gaps atz>zc are not random, but follow a definite trend.

Analysis of the recent data indicate that absorption line redshifts of QSOs are significantly correlated to their emission line redshifts. It is concluded that the absorption lines originate in materials intrinsic to the QSOs.

A gap in a distribution is the interval between two consecutive values. Gaps in the emission line redshift distribution of QSOs are analysed using up-to-date data comprising 371 objects. It is found that the distribution of gaps is not random, but follows a definite trend, depending on the mean value of the redshift in the region.

90 emission line profiles, constituting 30 Balmer lines and 55 forbidden and 5 other permitted lines, from 31 objects comprising of S1, S2, S3 classes of Seyfert galaxies, H II regions and QSOs, are analysed. A new mathematical representation of the profile is introduced by fitting the blue and red sides of the profile to Chebychev polynomials and the top to an inverted parabola. Parameters developed from these fittings are used to define indices of asymmetry and kurtosis. Asymmetry, kurtosis and FWHM are computed for all the profiles.

Absorption features shown by QSOs may be identified and measured as reported absorption redshift systems, or may remain unidentified and not measured. The features are believed to be observed in objects with high emission redshifts (zem), although no quantitative analysis exists to examine any such preferential trend, except that by Basu (1982). However, redshift data have since increased enormously both in range of the redshift spectrum and in number. Furthermore, the earlier analysis was based on only the reported absorption redshifts while unidentified absorption features were not dealt with. The present paper analyses the updated data, both identified and unidentified features. It is found that absorption features may be expressed as exponential function ofzem, and upper limits are set for the percentage of QSOs showing absorption features. Finally, an entirely new method of analysis confirms the earlier conclusion of Basu (1982) that the appearance of absorbing clouds is closely associated with the creation of the QSOs, the two may be having a common cause. It is suggested that ‘absorption QSOs’ may be a separate class of QSOs whose birth is accompanied with creation of absorbing clouds.

Distribution of the redshift difference (?z) between emission and absorption lines of QSOs is ‘half-gaussian’. Also, the quantity ?z increases with increase in emission line redshift (zem). The correlation between the two quantities (?z andzem) is statistically significant. The interpretation of the results indicate that the co-moving density of absorbing clouds decreases with redshift and that the absorbing clouds are associated with the QSOs rather than completely unrelated intervening material.

Significant correlation has been obtained between redshift and radio magnitude of quasars at 3 GHz emitted frequency.

Analysis of gaps in the emission line redshift distribution of 537 QSOs shows a single definite trend in the distribution of the gaps. The trend is similar for radio-quiet objects, radio sources and all QSO's taken together. However, the trend does not suggest any periodicity in redshifts in any of the three cases.

Gaps in the red-shift distribution of quasi-stellar objects and related peculiar galaxies have been studied using 205 sources. The result indicates certain definite trends in the distribution of the gaps but does not suggest any periodicity when the entire sample is considered.

Search lines used for identification of observed spectral lines in QSOs and hence for determination of redshifts have significant effects on the peaks and valleys in the emission and absorption redshift distributions of the present sample of QSOs, including ‘the 1.95 peak’.