Observational constraints on a decaying cosmological term
Abstract
We investigate the evolution of a universe with a decaying cosmological term (vacuum energy) that is assumed to be a function of the scale factor. In this model, while the cosmological term increases to the early universe, the radiation energy density is lower than the model with the cosmological "constant". We find that the effects of the decaying cosmological term on the expansion rate at the redshift z<2 is negligible. However, the decrease in the radiation density affects on the thermal history of the universe; e.g. the photon decoupling occurs at higher compared to the case of the standard \Lambda CDM model. As a consequence, a decaying cosmological term affects on the cosmic microwave background anisotropy. We show the angular power spectrum in D\Lambda CDM model and compare with the Wilkinson Microwave Anisotropy Probe (WMAP) data.
Keywords
Cite
@article{arxiv.astro-ph/0611258,
title = {Observational constraints on a decaying cosmological term},
author = {Riou Nakamura and Masa-aki Hashimoto and Kiyotomo Ichiki},
journal= {arXiv preprint arXiv:astro-ph/0611258},
year = {2008}
}
Comments
5 pages, 3 figures, Proceedings of International Symposium on Nuclear Astrophysics -Nuclei in the Cosmos IX-, CERN, Geneva, June 25-30, 2006