摘要Cosmological measurements suggest that our universe contains a dark energy component. In order to study the dark energy evolution, we constrain a parameterized dark energy equation of state w(z)=w0 + w1 z/1+z using the recent observational datasets: 157 Gold type Ia supernovae and the newly released 182 Gold type Ia supernovae by the maximum likelihood method. It is found that the best fit w(z) crosses -1 in the past and the present best fit value of w(0)<-1 obtained from 157 Gold-type Ia supernovae. The crossing of -1 is not realized and w0=-1 is not ruled out in 1σ confidence level for the 182 Gold-type Ia supernovae. It is also found that the range of parameter w0 is wide even in 1σ confidence level and the best fit w(z) is sensitive to the prior of Ωm.
Abstract：Cosmological measurements suggest that our universe contains a dark energy component. In order to study the dark energy evolution, we constrain a parameterized dark energy equation of state w(z)=w0 + w1 z/1+z using the recent observational datasets: 157 Gold type Ia supernovae and the newly released 182 Gold type Ia supernovae by the maximum likelihood method. It is found that the best fit w(z) crosses -1 in the past and the present best fit value of w(0)<-1 obtained from 157 Gold-type Ia supernovae. The crossing of -1 is not realized and w0=-1 is not ruled out in 1σ confidence level for the 182 Gold-type Ia supernovae. It is also found that the range of parameter w0 is wide even in 1σ confidence level and the best fit w(z) is sensitive to the prior of Ωm.
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2007, Vol. 24 
