Wednesday, December 14, 2011

1112.2911 (E. P. Berni Ann Thushari et al.)

Constraints from SNIa and CMB temperature observations on a Decaying Cosmological term    [PDF]

E. P. Berni Ann Thushari, Riou Nakamura, Mikio Ikeda, Masa-aki Hashimoto
We re-investigate the cosmic thermal evolution with a cosmological term which decay into photon. We assume that the cosmological term is a function of the scale factor that increases toward the early universe. We put on the constraints from recent type Ia supernovae (SNIa) by Union-2 compilation and the cosmic microwave background (CMB) temperature at $0.02 < z < 3$. From SNIa, we find that the effects of a decaying cosmological term on the cosmic expansion rate should be very small at $z < 1.5$. On the other hand, we obtain the severe constraints for parameters from the CMB temperature observations. This results mean the temperature can be still lower than the case of the standard cosmological model. Its should only affect the thermal evolution at the earlier epoch. Therefore we need to do analysis precisely such as the newest WMAP observational data.
View original: http://arxiv.org/abs/1112.2911

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