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arXiv 1401.4064astro-ph.CO
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通过对SDSS-II和SNLS超新星样品的联合分析改进宇宙学约束

Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples

M. Betoule, R. Kessler, J. Guy, J. Mosher, D. Hardin, R. Biswas, P. Astier, P. El-Hage, M. Konig, S. Kuhlmann, J. Marriner, R. Pain, N. Regnault, C. Balland, B.… 展开作者

M. Betoule, R. Kessler, J. Guy, J. Mosher, D. Hardin, R. Biswas, P. Astier, P. El-Hage, M. Konig, S. Kuhlmann, J. Marriner, R. Pain, N. Regnault, C. Balland, B. A. Bassett, P. J. Brown, H. Campbell, R. G. Carlberg, F. Cellier-Holzem, D. Cinabro, A. Conley, C. B. D'Andrea, D. L. DePoy, M. Doi, R. S. Ellis, S. Fabbro, A. V. Filippenko, R. J. Foley, J. A. Frieman, D. Fouchez, L. Galbany, A. Goobar, R. R. Gupta, G. J. Hill, R. Hlozek, C. J. Hogan, I. M. Hook, D. A. Howell, S. W. Jha, L. Le Guillou, G. Leloudas, C. Lidman, J. L. Marshall, A. Möller, A. M. Mourão, J. Neveu, R. Nichol, M. D. Olmstead, N. Palanque-Delabrouille, S. Perlmutter, J. L. Prieto, C. J. Pritchet, M. Richmond, A. G. Riess, V. Ruhlmann-Kleider, M. Sako, K. Schahmaneche, D. P. Schneider, M. Smith, J. Sollerman, M. Sullivan, N. A. Walton, C. J. Wheeler

摘要:

我们目前的宇宙学约束从一个联合分析的Ia型超新星(SN Ia)观测获得的SDSS-II和SNLS合作。该数据集包括几个低红移样本(z<0.1),SDSS-II的所有3个季节(0.05 < z < 0.4),SNLS的3年(0.2 <z < 1)和全部\ntotc光谱证实的Ia型超新星,具有高质量的光变曲线。我们遵循SNLS 3年数据分析的方法和假设,但以下重要改进除外:1)在SALT 2光变曲线模型的训练和哈勃图分析中增加了经SDSS-II光谱学确认的完整Ia型超新星样本(\nsdssc SNe),2)SNLS和SDSS测量的相互校准和光度校准中的系统不确定性的降低,对宇宙学分析进行了盲测; 3)对与超新星Ia光变曲线的SALT 2模拟相关的系统误差进行了彻底的研究。我们为SDSS-II和SNLS样品制作了重新校准的Ia超新星光变曲线和相关距离。大SDSS-II样本为哈勃图提供了一个有效的、独立的、低z的锚点,并减少了低z SN样本中校准系统的系统误差。对于平坦的LCDM宇宙学,我们发现Omega_m=0.295+-0.034(stat+sys),这个值与普朗克和WMAP实验中最新的CMB测量值一致。我们的结果是1.8sigma(stat+sys)不同于先前公布的SNLS 3年数据的结果。这一变化主要是由于SNLS光度校准的改进。当结合CMB约束时,我们测量了一个常数暗能量状态方程参数w=-1.018+-0.057(stat+sys)的平坦宇宙。添加BAO距离测量给出了类似的约束:w=-1.027+-0.055。

英文摘要:

We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The data set includes several low-redshift samples (z<0.1), all 3 seasons from the SDSS-II (0.05 < z < 0.4), and 3 years from SNLS (0.2 <z < 1) and totals \ntotc spectroscopically confirmed type Ia supernovae with high quality light curves. We have followed the methods and assumptions of the SNLS 3-year data analysis except for the following important improvements: 1) the addition of the full SDSS-II spectroscopically-confirmed SN Ia sample in both the training of the SALT2 light curve model and in the Hubble diagram analysis (\nsdssc SNe), 2) inter-calibration of the SNLS and SDSS surveys and reduced systematic uncertainties in the photometric calibration, performed blindly with respect to the cosmology analysis, and 3) a thorough investigation of systematic errors associated with the SALT2 modeling of SN Ia light-curves. We produce recalibrated SN Ia light-curves and associated distances for the SDSS-II and SNLS samples. The large SDSS-II sample provides an effective, independent, low-z anchor for the Hubble diagram and reduces the systematic error from calibration systematics in the low-z SN sample. For a flat LCDM cosmology we find Omega_m=0.295+-0.034 (stat+sys), a value consistent with the most recent CMB measurement from the Planck and WMAP experiments. Our result is 1.8sigma (stat+sys) different than the previously published result of SNLS 3-year data. The change is due primarily to improvements in the SNLS photometric calibration. When combined with CMB constraints, we measure a constant dark-energy equation of state parameter w=-1.018+-0.057 (stat+sys) for a flat universe. Adding BAO distance measurements gives similar constraints: w=-1.027+-0.055.

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