Abstract
In order to investigate the nature of the redshifts of QSOs, Hubble diagrams have been plotted. First, [log (cz),m v ] pairs have been plotted for a sample of 252 QSOs. This sample has been drawn from the recent catalogue (Burbidgeet al., 1977) of 633 QSOs after excluding those for which either the redshifts are uncertain or theV magnitudes are not known accurately. Before plotting,K-correction has been applied to theV magnitudes. A least-squares linear fit has been obtained for this plot and, as a result, we get a slope of 0.165±0.012 against 0.2 expected theoretically on the basis of the assumption that the QSOs are at cosmological distances implied by their redshifts. The discrepancy in the value of the slope has been attributed partly to the uncertainty in theK-correction and partly to the evolutionary effect. In order to eliminate the uncertainty due to theK-correction, [log (cz), logf(Hβ)] pairs have been plotted for a sample of 52 QSOs and a least-squares linear fit has been obtained which has a slope of −0.497±0.076, in close agreement with the theoretically expected value of −0.5. This lends support to the hypothesis that the redshifts of the QSOs are cosmological in nature. Finally, the evolutionary effect has been examined, and we conclude that the QSOs do evolve in luminosity in course of time.
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Thakur, R.K., Sapre, A.K. Redshifts and the Hubble diagrams of Quasi-Stellar Objects. Astrophys Space Sci 57, 119–139 (1978). https://doi.org/10.1007/BF00639050
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DOI: https://doi.org/10.1007/BF00639050