Constraints from the Old Quasar APM 08279+5255 on Two Classes of $Λ($t$)$-Cosmologies
| dc.creator | Jesus, J. F. | |
| dc.date | 2006-03-06 | |
| dc.date | 2007-11-23 | |
| dc.date.accessioned | 2026-07-07T11:42:30Z | |
| dc.date.available | 2026-07-07T11:42:30Z | |
| dc.description | The viability of two different classes of $Λ(t)$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 cosmological term scales as $Λ(t)\sim R^{-n}$. The particular case $n=0$ describes the standard $Λ$CDM model whereas $n=2$ stands for the Chen and Wu model. For an estimated age of 2 Gyr, it is found that the power index has a lower limit $n> 0.21$, whereas for 3 Gyr the limit is $n > 0.6$. Since $n$ can not be so large as $\sim 0.81$, the $Λ$CDM and Chen and Wu models are also ruled out by this analysis. The second class of models is the one recently proposed by Wang and Meng which describes several $Λ(t)$CDM cosmologies discussed in the literature. By assuming that the true age is 2 Gyr it is found that the $ε$ parameter satisfies the lower bound $ε> 0.11$, while for 3 Gyr, a lower limit of $ε> 0.52$ is obtained. Such limits are slightly modified when the baryonic component is included. | |
| dc.description | 7 pages, 3 figures, job presented at the IWARA 2005. Revised paper to match version to be published on GRG | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0603142 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0603142 | |
| dc.identifier | Gen.Rel.Grav.40:791-798,2008 | |
| dc.identifier | doi:10.1007/s10714-007-0533-0 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/200906 | |
| dc.subject | Astrophysics | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.title | Constraints from the Old Quasar APM 08279+5255 on Two Classes of $Λ($t$)$-Cosmologies | |
| dc.type | text |