Observational tests for Λ(t)CDM cosmology
Observational tests for Λ(t)CDM cosmology
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DOI：
10.1088/1475-7516/2011/08/022
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发表时间：
2010-07
影响因子：
6.4
通讯作者：
C. Pigozzo;M. A. Dantas;S. Carneiro;S. Carneiro;J. Alcaniz
中科院分区：
文献类型：
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作者：
C. Pigozzo;M. A. Dantas;S. Carneiro;S. Carneiro;J. Alcaniz
我们研究了一类宇宙学模型的观测可行性，其中真空能量密度随哈勃参数线性衰减，导致在后期产生冷暗物质粒子。与平坦ΛCDM情形类似，在这类Λ（t）CDM情形中，只有一个自由参数需要由数据调整，即物质密度参数。为了进行我们的分析，我们使用三个最新的SNe Ia编译集（Union2，SDSS和Constitution），沿着与z = 0.2和z = 0.35处的BAO峰值的距离的当前测量值以及CMB功率谱的第一个声学峰值的位置。我们表明，在χ2统计量方面，这两个模型提供了良好的拟合数据和相似的结果。使用当前的SDSS和Constitution SNe Ia汇编，研究了由于SNe光曲线拟合方法（SALT 2和MLCS 2k2）导致的参数估计差异的定量分析。还使用2dFGRS进行了物质功率谱分析，与SDSS和Constitution MLCS2k2数据的约束条件具有很好的一致性。
We investigate the observational viability of a class of cosmological models in which the vacuum energy density decays linearly with the Hubble parameter, resulting in a production of cold dark matter particles at late times. Similarly to the flat ΛCDM case, there is only one free parameter to be adjusted by the data in this class of Λ(t)CDM scenarios, namely, the matter density parameter. To perform our analysis we use three of the most recent SNe Ia compilation sets (Union2, SDSS and Constitution) along with the current measurements of distance to the BAO peaks at z = 0.2 and z = 0.35 and the position of the first acoustic peak of the CMB power spectrum. We show that in terms of χ2 statistics both models provide good fits to the data and similar results. A quantitative analysis discussing the differences in parameter estimation due to SNe light-curve fitting methods (SALT2 and MLCS2k2) is studied using the current SDSS and Constitution SNe Ia compilations. A matter power spectrum analysis using the 2dFGRS is also performed, providing a very good concordance with the constraints from the SDSS and Constitution MLCS2k2 data.