Measurements of Ω and Λ from 42 high-redshift supernovae
Measurements of Ω and Λ from 42 high-redshift supernovae
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DOI：
10.1086/307221
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发表时间：
1999-06-01
影响因子：
4.9
通讯作者：
Couch, WJ
中科院分区：
文献类型：
--
作者：
Perlmutter, S;Aldering, G;Couch, WJ
我们报告的质量密度，欧米茄（M），和宇宙常数能量密度，欧米茄（λ），宇宙的基础上，超新星宇宙学计划发现的42个Ia型超新星的分析测量。这些超新星的星等-红移数据（红移在0.18和0.83之间）与一组来自卡兰/托洛洛超新星巡天的超新星（红移低于0.1）进行了联合拟合，以获得宇宙学参数的值。所有超新星的峰值星等都用超新星Ia的光变曲线宽度-光度关系来标准化。测量产生宇宙学参数的联合概率分布，其近似关系为0.8 Ω（M）-0.6 Ω（λ），在感兴趣的区域中近似为-0.2 +/-0.1（Ω（M）小于或近似于1.5）。对于一个平坦的（Ω（M）+ Ω（λ）= 1）宇宙学，我们发现Ω（M）（平坦）= 0.28（-0.08）（+0.09）（1 sigma统计）（-0.04）（+0.05）（已识别的系统学）。这些数据与最简单的暴胀宇宙模型--λ = 0的平坦宇宙学非常不一致。一个开放的、λ = 0的宇宙学也不能很好地拟合数据：数据表明宇宙学常数是非零的和正的，置信度P（λ> 0）= 99%，包括确定的系统不确定性。宇宙相对于哈勃时间的最佳拟合年龄是t（0）（平坦）= 14.9（-1.1）（+1.4）（0.63/h）Gyr。我们的样本量允许我们进行各种统计测试，以检查可能的系统误差和偏差。我们发现无论是主机红化分布或Malmquist偏差之间的低红移卡兰/Tololo样品和我们的高红移样品没有显着差异。排除那些少数的超新星是异常的颜色过剩或拟合残差不会显着改变结果。无论是否使用宽度-光度关系来标准化超新星峰值的大小，结论都是可靠的。我们讨论和约束，在可能的情况下，假设的宇宙常数的替代品。
We report measurements of the mass density, Omega(M), and cosmological-constant energy density, Omega(Lambda), of the universe based on the analysis of 42 type Ia supernovae discovered by the Supernova Cosmology Project. The magnitude-redshift data for these supernovae, at redshifts between 0.18 and 0.83, are fitted jointly with a set of supernovae from the Calan/Tololo Supernova Survey, at redshifts below 0.1, to yield values for the cosmological parameters. All supernova peak magnitudes are standardized using a SN Ia light-curve width-luminosity relation. The measurement yields a joint probability distribution of the cosmological parameters that is approximated by the relation 0.8 Omega(M) - 0.6 Omega(Lambda), approximate to -0.2 +/- 0.1 in the region of interest (Omega(M) less than or similar to 1.5). For a flat (Omega(M) + Omega(Lambda) = 1) cosmology we find Omega(M)(flat) = 0.28(-0.08)(+0.09) (1 sigma statistical)(-0.04)(+0.05) (identified systematics). The data are strongly inconsistent with a Lambda = 0 flat cosmology, the simplest inflationary universe model. An open, Lambda = 0 cosmology also does not fit the data well: the data indicate that the cosmological constant is nonzero and positive, with a confidence of P(Lambda > 0)= 99%, including the identified systematic uncertainties. The best-fit age of the universe relative to the Hubble time is t(0)(flat) = 14.9(-1.1)(+1.4)(0.63/h) Gyr for a flat cosmology. The size of our sample allows us to perform a variety of statistical tests to check for possible systematic errors and biases. We find no significant differences in either the host reddening distribution or Malmquist bias between the low-redshift Calan/Tololo sample and our high-redshift sample. Excluding those few supernovae that are outliers in color excess or fit residual does not significantly change the results. The conclusions are also robust whether or not a width-luminosity relation is used to standardize the supernova peak magnitudes. We discuss and constrain, where possible, hypothetical alternatives to a cosmological constant.