Constraints from the Old Quasar APM 08279+5255 on Two Classes of $\Lambda ($t$)$-Cosmologies

J. F. Jesus

The viability of two different classes of $\Lambda (t)$CDM cosmologies is tested by using the APM 08279+5255, an old quasar at redshift $z=3.91$. In the first class of models, the cosmo…