Mapping the Integrated Sachs-Wolfe Effect
Mapping the Integrated Sachs-Wolfe Effect
复制标题
绘制综合萨克斯-沃尔夫效应
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
S. Dodelson
中科院分区：
文献类型：
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作者：
A. Manzotti;S. Dodelson
在大尺度上，宇宙微波背景（CMB）的各向异性不仅反映了原初密度场，还反映了光子穿越大尺度结构的衰减引力势时的能量增益，这就是所谓的积分萨克斯 - 沃尔夫（ISW）效应。在宇宙学家努力理解这些尺度上的宇宙时，将各向异性信号分解为原初部分和ISW成分（大尺度上的主要次级效应）比以往任何时候都更加紧迫。我们提出了一种似然技术，用于结合对CMB的测量、星系分布以及引力透镜地图来提取ISW信号。我们用模拟数据测试了该技术，结果表明我们可以成功地利用所有数据集一起重建ISW地图。然后，我们展示了从实际数据组合中获得的ISW地图：美国国家射电天文台甚大阵天空观测（NVSS）星系观测、温度各向异性以及普朗克卫星绘制的透镜地图。这幅地图表明，使用所采用的数据集并假设线性物理，从冷斑区域重建的ISW信号来看，没有证据表明CMB中这种大尺度异常完全是由ISW引起的。然而，来自NVSS红移范围之外的低红移空洞的大尺度结构起源仍然是可能的。最后，我们表明，由于更好的大尺度透镜重建，未来的观测将能够提高重建的信噪比，目前信噪比主要来自星系观测。
On large scales, the anisotropies in the cosmic microwave background (CMB) reflect not only the primordial density field but also the energy gain when photons traverse decaying gravitational potentials of large scale structure, what is called the integrated Sachs-Wolfe (ISW) effect. Decomposing the anisotropy signal into a primordial piece and an ISW component, the main secondary effect on large scales, is more urgent than ever as cosmologists strive to understand the Universe on those scales. We present a likelihood technique for extracting the ISW signal combining measurements of the CMB, the distribution of galaxies, and maps of gravitational lensing. We test this technique with simulated data showing that we can successfully reconstruct the ISW map using all the data sets together. Then we present the ISW map obtained from a combination of real data: the NRAO VLA sky survey (NVSS) galaxy survey, temperature anisotropies, and lensing maps made by the Planck satellite. This map shows that, with the data sets used and assuming linear physics, there is no evidence, from the reconstructed ISW signal in the Cold Spot region, for an entirely ISW origin of this large scale anomaly in the CMB. However a large scale structure origin from low redshift voids outside the NVSS redshift range is still possible. Finally we show that future surveys, thanks to a better large scale lensing reconstruction will be able to improve the reconstruction signal to noise which is now mainly coming from galaxy surveys.