Supernova Ia Constraints on a Time-variable Cosmological “Constant”
Supernova Ia Constraints on a Time-variable Cosmological “Constant”
复制标题
超新星 Ia 对时变宇宙学“常数”的约束
DOI：
10.1086/308575
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Bharat Ratra
中科院分区：
文献类型：
--
作者：
Silviu Podariu;Bharat Ratra
一个标量场的能量密度V（V）-α，α > 0，表现得像一个随时间变化的宇宙学常数，它对现在的能量密度有很大的贡献。这个空间平坦模型的预测相比，最近Ia型超新星的视星等与红移数据。模型参数空间的一个大区域与当前的观测结果一致。（这些约束是基于精确的标量场模型运动方程，而不是广泛使用的与时间无关的状态方程流体近似运动方程。我们研究的后果，也纳入约束条件，从最近的测量哈勃参数和宇宙的年龄在常数和随时间变化的宇宙常数模型。我们还研究了使用一个noninformative前的密度参数的效果。
The energy density of a scalar field ϕ with potential V(ϕ) ∝ ϕ-α, α > 0, behaves like a time-variable cosmological constant that could contribute significantly to the present energy density. Predictions of this spatially flat model are compared to recent Type Ia supernova apparent magnitude versus redshift data. A large region of model parameter space is consistent with current observations. (These constraints are based on the exact scalar field model equations of motion, not on the widely used time-independent equation of state fluid approximation equations of motion.) We examine the consequences of also incorporating constraints from recent measurements of the Hubble parameter and the age of the universe in the constant and time-variable cosmological constant models. We also study the effect of using a noninformative prior for the density parameter.