科研之友
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摘要
The creation of cold dark matter (CCDM) can explain the present accelerating cosmic expansion without appealing to dark energy. In this paper, we investigate the age problem of CCDM models by considering five old high red-shift objects (OHROs) (old ratio galaxy 3C 65, old galaxy LBDS 53W069, old galaxy LBDS 53W091, high redshift quasar B1422 + 231, old quasar APM 08279 + 5255). Two concrete CCDM models, i.e., the LSS and the LJO, are studied. Using the recent SNIa, BAO and H(z) observational data to constrain the model parameters, we can estimate the cosmic age with the model parameters that are their best fit values. By comparing the estimated cosmic age with the age of OHROs, we find that for the LSS, the ages of five OHROs are less than the cosmic age at the same redshift, while for the LJO, the conclusion depends sensitively on both the value for the age of APM 08279 + 5255 and the value of H-0. So, to determine whether the age problem exists for the LJO, we need more precise results on the age of APM 08279 + 5255 and the value of the present Hubble parameter.
