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arXiv 0804.4142astro-ph
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来自新、旧和组合超新星数据集的改进的宇宙学约束

Improved Cosmological Constraints from New, Old and Combined Supernova Datasets

M. Kowalski, D. Rubin, G. Aldering, R. J. Agostinho, A. Amadon, R. Amanullah, C. Balland, K. Barbary, G. Blanc, P. J. Challis, A. Conley, N. V. Connolly, R. Cov… 展开作者

M. Kowalski, D. Rubin, G. Aldering, R. J. Agostinho, A. Amadon, R. Amanullah, C. Balland, K. Barbary, G. Blanc, P. J. Challis, A. Conley, N. V. Connolly, R. Covarrubias, K. S. Dawson, S. E. Deustua, R. Ellis, S. Fabbro, V. Fadeyev, X. Fan, B. Farris, G. Folatelli, B. L. Frye, G. Garavini, E. L. Gates, L. Germany, G. Goldhaber, B. Goldman, A. Goobar, D. E. Groom, J. Haissinski, D. Hardin, I. Hook, S. Kent, A. G. Kim, R. A. Knop, C. Lidman, E. V. Linder, J. Mendez, J. Meyers, G. J. Miller, M. Moniez, A. M. Mourao, H. Newberg, S. Nobili, P. E. Nugent, R. Pain, O. Perdereau, S. Perlmutter, M. M. Phillips, V. Prasad, R. Quimby, N. Regnault, J. Rich, E. P. Rubenstein, P. Ruiz-Lapuente, F. D. Santos, B. E. Schaefer, R. A. Schommer, R. C. Smith, A. M. Soderberg, A. L. Spadafora, L. -G. Strolger, M. Strovink, N. B. Suntzeff, N. Suzuki, R. C. Thomas, N. A. Walton, L. Wang, W. M. Wood-Vasey, J. L. Yun

摘要:

我们提出了一个新的编译Ia型超新星(SNe Ia),一个新的数据集的低红移附近的哈勃流SNe和新的分析程序,这些异构的编译工作。这个414个超新星Ia的“联盟”汇编,在选择切割后减少到307个超新星,包括超新星遗产调查和ESSENCE调查最近的大样本超新星Ia,旧的数据集,以及最近扩展的HST观测到的遥远超新星数据集。一个单一的,一致的和盲目的分析程序被用于所有的各种SN Ia子样本,并实施了一个新的程序,一致的权重异质数据集和拒绝离群值。我们提出了这个联盟汇编的最新结果,并讨论了这个新汇编的宇宙学约束及其与其他宇宙学测量(CMB和BAO)的结合。对于一个平坦的LCDM宇宙,我们从超新星中得到的暗能量密度的约束是$Ω_Λ= 0.713^{+0.027}_{-0.029} (stat)}^{+0.036}_{-0.039} (sys)}$。假设状态方程参数$w$为常数,则SNe、BAO和CMB的组合约束给出$w=-0.969^{+0.059}_{-0.063}(stat)^{+0.063}_{-0.066} (sys)$。虽然我们的结果是一致的宇宙学常数,我们得到的$w$,随红移变化的限制相对较弱。特别地,当前SN数据尚未显著地将$w$约束在$z>1$。随着我们附近新的哈勃流SNe Ia的加入,这些由此产生的宇宙学约束是目前最严格的。

英文摘要:

We present a new compilation of Type Ia supernovae (SNe Ia), a new dataset of low-redshift nearby-Hubble-flow SNe and new analysis procedures to work with these heterogeneous compilations. This ``Union'' compilation of 414 SN Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older datasets, as well as the recently extended dataset of distant supernovae observed with HST. A single, consistent and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers. We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO). The constraint we obtain from supernovae on the dark energy density is $Ω_Λ= 0.713^{+0.027}_{-0.029} (stat)}^{+0.036}_{-0.039} (sys)}$, for a flat, LCDM Universe. Assuming a constant equation of state parameter, $w$, the combined constraints from SNe, BAO and CMB give $w=-0.969^{+0.059}_{-0.063}(stat)^{+0.063}_{-0.066} (sys)$. While our results are consistent with a cosmological constant, we obtain only relatively weak constraints on a $w$ that varies with redshift. In particular, the current SN data do not yet significantly constrain $w$ at $z>1$. With the addition of our new nearby Hubble-flow SNe Ia, these resulting cosmological constraints are currently the tightest available.

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