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arXiv 0905.3410astro-ph.COastro-ph.IM
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优化重子声学振荡巡天II:曲率、红移和外部数据集

Optimizing baryon acoustic oscillation surveys II: curvature, redshifts, and external datasets

David Parkinson, Martin Kunz, Andrew R. Liddle, Bruce A. Bassett, Robert C. Nichol, Mihran Vardanyan

摘要:

我们扩展了我们的研究优化的大型重子声学振荡(BAO)调查返回的最佳约束的暗能量,建立在本系列论文(帕金森等2007年)。调查星系被假定为预先选定的活动,恒星形成星系观察到他们的线发射与一个恒定的数密度在整个红移箱。恒星形成星系在1.6 < z < 2的区域有一个红移沙漠,因此这个红移范围被排除在分析之外。我们使用Seo & Eisenstein(2007)拟合公式来计算BAO测量的准确性,只使用功率谱的振荡部分的信息作为距离和膨胀率标尺。我们超越了我们以前的分析,包括曲率的最佳调查配置和更新预期的普朗克和SDSS的约束的影响。我们再次发现,最佳的调查策略包括最小化曝光时间和最大化调查区域(在仪器限制范围内),所有的时间都应该花在观测低红移范围(z<1.6),而不是超越红移沙漠,z>2。我们发现,当假设宇宙是平坦的时,最佳巡天测量的红移范围是0.1 < z <0.7,但如果把曲率作为一个讨厌的参数,我们需要把最大红移推到1.35,以消除曲率和演化的暗能量之间的简并。包含预期的其他数据集(如WiggleZ,BOSS和第三阶段SN-Ia调查)消除了测量低于红移0.9的必要性,并将最大红移推高至1.5。我们讨论的考虑因素,在确定最佳的调查策略,在真正的基础宇宙学模型的不确定性。

英文摘要:

We extend our study of the optimization of large baryon acoustic oscillation (BAO) surveys to return the best constraints on the dark energy, building on Paper I of this series (Parkinson et al. 2007). The survey galaxies are assumed to be pre-selected active, star-forming galaxies observed by their line emission with a constant number density across the redshift bin. Star-forming galaxies have a redshift desert in the region 1.6 < z < 2, and so this redshift range was excluded from the analysis. We use the Seo & Eisenstein (2007) fitting formula for the accuracies of the BAO measurements, using only the information for the oscillatory part of the power spectrum as distance and expansion rate rulers. We go beyond our earlier analysis by examining the effect of including curvature on the optimal survey configuration and updating the expected `prior' constraints from Planck and SDSS. We once again find that the optimal survey strategy involves minimizing the exposure time and maximizing the survey area (within the instrumental constraints), and that all time should be spent observing in the low-redshift range (z<1.6) rather than beyond the redshift desert, z>2. We find that when assuming a flat universe the optimal survey makes measurements in the redshift range 0.1 < z <0.7, but that including curvature as a nuisance parameter requires us to push the maximum redshift to 1.35, to remove the degeneracy between curvature and evolving dark energy. The inclusion of expected other data sets (such as WiggleZ, BOSS and a stage III SN-Ia survey) removes the necessity of measurements below redshift 0.9, and pushes the maximum redshift up to 1.5. We discuss considerations in determining the best survey strategy in light of uncertainty in the true underlying cosmological model.

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