Constraints on a vacuum energy from both SNIa and CMB temperature observations

Riou Nakamura, E. P.Berni Ann Thushari, Mikio Ikeda, Masa Aki Hashimoto

Research output: Contribution to journalArticlepeer-review


We investigate the cosmic thermal evolution with a vacuum energy which decays into photon at the low redshift. We assume that the vacuum energy is a function of the scale factor that increases toward the early universe. We put on the constraints using recent observations of both type Ia supernovae (SNIa) by Union-2 compilation and the cosmic microwave background (CMB) temperature at the range of the redshift 0.01 < z < 3. From SNIa, we find that the effects of a decaying vacuum energy on the cosmic expansion rate should be very small but could be possible for z < 1.5. On the other hand, we obtain the severe constraints for parameters from the CMB temperature observations. Although the temperature can be still lower than the case of the standard cosmological model, it should only affect the thermal evolution at the early epoch.

Original languageEnglish
Article number528243
JournalAdvances in Astronomy
Publication statusPublished - 2012

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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