Cher Li: The Time Dilation of High Redshift Quasars: Insights from Bayesian Inference

<p dir="ltr">After decades of investigation, cosmological time dilation has recently been confirmed in the variability timescales of distant quasars. This study builds upon previous analyses by separating the cosmological signal from the effects of source population properties, specifically quasar bolometric luminosity and the rest-frame emission wavelength of observed variability. Using Bayesian modelling, the variability timescales in 190 quasars were examined. The findings indicate that the model incorporating all explanatory factors provided the best fit as indicated by marginal likelihoods. If the cosmological dependence is assumed to be of the form (1+z)^n, the inference yields 〖n=1.13〗_(-0.26)^(+0.35), aligning with the results of Lewis and Brewer (2023). This supports the hypothesis that quasar variability is driven by cosmological time dilation, challenging earlier conclusions by Hawkins (1993, 2001, 2010).</p>