X-Ray Temperatures for the Extended Medium-Sensitivity Survey High-Redshift Cluster Sample: Constraints on Cosmology and the Dark Energy Equation of State
X-Ray Temperatures for the Extended Medium-Sensitivity Survey High-Redshift Cluster Sample: Constraints on Cosmology and the Dark Energy Equation of State
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扩展中灵敏度巡天高红移星团样本的 X 射线温度：宇宙学和暗能量状态方程的约束
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发表时间：
2004
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通讯作者：
J. Henry
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作者：
J. Henry
我们用ASCA测量了爱因斯坦扩展中等灵敏度测量高红移(z≥0.3)样品中除一个外的所有星团的X射线温度(和光度)。我们将这些数据与低红移星系团的完整样本进行比较，这些样本也有温度测量，从而提供了宇宙学约束。对以前工作的改进包括：(1)扩大了高红移样品；(2)低红移比较样品的温度与高红移样品来自同一仪器；(3)消除了三个与目标红移相同(即不是真正偶然的)的EMSS星团和第四个ASCA通量远低于完备性极限的EMSS星团；(4)使用与N体模拟更接近的理论星团质量函数(Sheth-Torman函数)；(5)使用冷暗物质功率谱而不是幂定律；(6)使用具有任意物质密度和宇宙常数的一般宇宙学；(7)使用将宇宙学常数概括为精髓的宇宙学；(8)在星团光度-温度关系中包括温度测量误差和散射的影响；以及(9)对质量-温度关系的鲜为人知的归一化进行边缘化。我们在ΩM0-ΩΛ0平面上发现了一个与超新星Ia哈勃图和宇宙微波背景涨落所提供的约束带方向不同的允许带。所有三个频带在同一位置相交：ΩM0≈0.3，ΩΛ0≈0.7。我们测量的经典状态方程参数为w=-(0.42±0.21)(对于一个有趣的参数，置信度为68%)，与先前确定的上限一致。我们测量质量涨落功率谱的归一化为σ8=0.66±0.16(对于三个有趣的参数，置信度为68%)。对于我们的样本，只有σ8的系统误差大于统计误差；因此，它的误差取决于温度-质量归一化过程中的边际化细节。
We measure the X-ray temperature (and luminosity) with ASCA of all but one cluster in the Einstein Extended Medium-Sensitivity Survey (EMSS) high-redshift (z ≥ 0.3) sample. We compare these data to a complete sample of low-redshift clusters that also has temperature measurements, thereby providing cosmological constraints. Improvements over our previous work include (1) an enlarged high-redshift sample; (2) temperatures for the low-redshift comparison sample that come from the same instrument as the high-redshift sample; (3) the elimination of three EMSS clusters with the same redshift as the target (i.e., not truly serendipitous) and a fourth with an ASCA flux well below the completeness limit; (4) using a theoretical cluster mass function that more closely matches N-body simulations (the Sheth-Torman function); (5) using a cold dark matter power spectrum instead of a power law; (6) using a general cosmology with arbitrary matter density and cosmological constant; (7) using a cosmology that generalizes the cosmological constant to quintessence; (8) including the effects of temperature measurement errors and scatter in the cluster luminosity-temperature relation; and (9) marginalizing over the poorly known normalization of the mass-temperature relation. We find an allowed band in the Ωm0-ΩΛ0 plane of different orientation to the band of constraints provided by the supernovae Ia Hubble diagram and the cosmic microwave background fluctuations. All three bands intersect at the same place: Ωm0 ≈ 0.3, ΩΛ0 ≈ 0.7. We measure the quintessence equation-of-state parameter to be w = -(0.42 ± 0.21) (68% confidence for one interesting parameter), consistent with previously determined upper limits. We measure the normalization of the mass fluctuation power spectrum to be σ8 = 0.66 ± 0.16 (68% confidence for three interesting parameters). Systematic errors are larger than the statistical errors only for σ8 with our sample; thus the errors for it depend on the details of the marginalization over the temperature-mass normalization.