
Cosmic microwave background radiation temperature in a dissipative universeCosmic microwave background radiation temperature in a dissipative universeAA00773624 
"/Komatsu, Nobuyoshi(1000020436827)/"Komatsu, Nobuyoshi ,
"/Kimura, Shigeo(1000070272953)/"Kimura, Shigeo
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, p.043507 , 20150806 , American Physical Society
ISSN:15507998
NCID:AA00773624
Description
The relationship between the cosmic microwave background radiation temperature and the redshift, i.e., the Tz relation, is examined in a phenomenological dissipative model. The model contains two constant terms, as if a nonzero cosmological constant Λ and a dissipative process are operative in a homogeneous, isotropic, and spatially flat universe. The Tz relation is derived from a general radiative temperature law, as appropriate for describing nonequilibrium states in a creation of cold dark matter model. Using this relation, the radiation temperature in the late Universe is calculated as a function of a dissipation rate ranging from μ=0, corresponding to a nondissipative lambda cold dark matter model, to μ=1, corresponding to a fully dissipative creation of cold dark matter model. The Tz relation for μ=0 is linear for standard cosmology and is consistent with observations. However, with increasing dissipation rate μ, the radiation temperature gradually deviates from a linear law because the effective equationofstate parameter varies with time. When the background evolution of the Universe agrees with a finetuned pure lambda cold dark matter model, the Tz relation for low μ matches observations, whereas the Tz relation for high μ does not. Previous work also found that a weakly dissipative model accords with measurements of a growth rate for clustering related to structure formations. These results imply that low dissipation is likely for the Universe. The weakly dissipative model should be further constrained by recent observations. © 2015 American Physical Society.
FullText
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