SKA Weak Lensing II: Simulated Performance and Survey Design Considerations
SKA Weak Lensing II: Simulated Performance and Survey Design Considerations
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DOI：
10.1093/mnras/stw2104
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发表时间：
2016-01
影响因子：
4.8
通讯作者：
A. Bonaldi;I. Harrison;S. Camera;Michael L. Brown
中科院分区：
文献类型：
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作者：
A. Bonaldi;I. Harrison;S. Camera;Michael L. Brown
我们构建了一个管道模拟弱透镜宇宙学调查与平方公里阵列（SKA），作为输入望远镜灵敏度曲线;相关源通量，大小和红移分布;一个简单的电离层模型;源红移和椭圆测量误差。然后，我们使用这个模拟管道来优化第一次部署SKA（SKA 1）时进行的为期2年的弱透镜调查。我们的评估是基于恢复的剪切功率谱的总信噪比，我们发现这一指标与标准暗能量品质因数非常相关。我们首先考虑频带的选择，在较低频率下的数量计数增加与较低的分辨率之间进行权衡;我们的分析强烈倾向于SKA-MID望远镜的较高频率频带2（950-1760 MHz）信道，而不是较低频率频带1（350-1050 MHz）。通过允许频带2的中心向较低的频率（大约1.1 GHz）移动，将获得最佳结果。然后，我们继续考虑调查规模，发现5,000平方度的面积是最佳的大多数SKA 1仪器配置。最后，我们预测了一个弱透镜调查的SKA的第二次部署的性能。增加的调查规模（3$\pi $\，steradian）和灵敏度将信噪比和暗能量指标提高了两个数量级。
We construct a pipeline for simulating weak lensing cosmology surveys with the Square Kilometre Array (SKA), taking as inputs telescope sensitivity curves; correlated source flux, size and redshift distributions; a simple ionospheric model; source redshift and ellipticity measurement errors. We then use this simulation pipeline to optimise a 2-year weak lensing survey performed with the first deployment of the SKA (SKA1). Our assessments are based on the total signal-to-noise of the recovered shear power spectra, a metric that we find to correlate very well with a standard dark energy figure of merit. We first consider the choice of frequency band, trading off increases in number counts at lower frequencies against poorer resolution; our analysis strongly prefers the higher frequency Band 2 (950-1760 MHz) channel of the SKA-MID telescope to the lower frequency Band 1 (350-1050 MHz). Best results would be obtained by allowing the centre of Band 2 to shift towards lower frequency, around 1.1 GHz. We then move on to consider survey size, finding that an area of 5,000 square degrees is optimal for most SKA1 instrumental configurations. Finally, we forecast the performance of a weak lensing survey with the second deployment of the SKA. The increased survey size (3$\pi$\,steradian) and sensitivity improves both the signal-to-noise and the dark energy metrics by two orders of magnitude.