Peaks and Periodicities in the Redshift Distribution of Quasi-Stellar Object

Abstract

There have been claims from time to time that there are periodicities in the redshift distribution of QSOs. These claims are examined from various statistical angles for a sample of 2164 QSO redshifts, with redshifts lying in the range 0.025 – 4.43 taken from the latest compilation (1993) by Hewitt & Burbidge. We have not included QSOs whose redshifts were obtained by ‘grism’ technique, because of a possible selection effect (Scott 1991). For our analysis we use several staistical techniques, including the Burbidge - O'Dell type Power spectrum analysis (1972), the Rayleigh test, the Kolmogorov-Smirnov test, and the so called ‘Comb-tooth’ template test. the tests are not inter related and have the advantage of checking the claim for nonuniformity of the distribution from various independent angles. We have also carried out Monte Carlo simulations of the redshift distribution of QSOs to check for any systematic effect that can give rise to a spurious periodic effect.