Age of high redshift objects-a litmus test for the dark energy models

The discovery of the quasar, the APM 08279+5255 at z=3.91 whose age is 2-3 Gyr has once again led to “age crisis”. The noticeable fact about this object is that it cannot be accommodated in a universe with Ωm=0.27, currently accepted value of matter density parameter and ω=const. In this work, we explore the concordance of various dark energy parameterizations (w(z) models) with the age estimates of the old high redshift objects. It is alarming to note that the quasar cannot be accommodated in any dark energy model even for Ωm=0.23, which corresponds to 1σ deviation below the best fit value provided by WMAP. There is a need to look for alternative cosmologies or some other dark energy parameterizations which allow the existence of the high redshift objects.