We present a new method for constructing maps of the secondary temperature fluctuations imprinted on the cosmic microwave background (CMB) radiation by photons propagating through the evolving cosmic gravitational potential. Large cosmological N-body simulations are used to calculate the complete non-linear evolution of the peculiar gravitational potential. Tracing light rays back through the past lightcone of a chosen observer accurately captures the temperature perturbations generated by linear (the integrated Sachs-Wolfe or ISW effect) and non-linear (the Rees-Sciama or RS effect) evolution. These effects give rise to three kinds of non-linear features in the temperature maps. (a) In overdense regions, converging flows of matter induce cold spots of order 100 Mpc in extent which can dominate over the ISW effect at high redshift, and are surrounded by hot rings. (b) In underdense regions, the RS effect enhances ISW cold spots which can be surrounded by weak hot rings. (c) Transverse motions of large lumps of matter produce characteristic dipole features, consisting of adjacent hot and cold spots separated by a few tens of Megaparsecs. These non-linear features are not easily detectable; they modulate the ISW sky maps at about the 10 percent level. The RS effect causes the angular power spectrum to deviate from linear theory at l~50 and generates non-Gaussianity, skewing the one-point distribution function to negative values. Cold spots of similar angular size, but much smaller amplitude than the CMB cold spot reported by Cruz et al. are produced. Joint analysis of our maps and the corresponding galaxy distribution may enable techniques to be developed to detect these non-linear, non-Gaussian features. Our maps are available at http://astro.dur.ac.uk/~cai/ISW
Integrated Sachs Wolfe Effect and Rees Sciama Effect
自R. K. Sachs和A. M. Wolfe预言了宇宙微波背景（CMB）中各向异性的存在，并且自10年前首次观测到积分萨克斯-沃尔夫效应（ISW）以来。ISW效应为我们提供了一个独特的宇宙加速膨胀的探测器。大尺度结构与CMB之间的互相关是从数据中提取ISW效应的最有前途的方法。在这篇文章中，我们回顾了ISW效应的物理学，并总结了最近的观测结果和解释。
Evidence for a sign change of the ISW effect in the very recent universe? hot voids and cold overdensities at $z<0.03$
Institute of Theoretical Astrophysics, University of Oslo（奥斯陆大学理论天体物理研究所）；Instituto de Astronomía Teórica y Experimental, CONICET-UNC（CONICET-科尔多瓦大学理论与实验天文学研究所）；Observatorio Astronómico de Córdoba, UNC（科尔多瓦天文台，科尔多瓦大学）
Dynamical Test of Cosmic Acceleration: $k$-nearest Neighbor Cross Correlation of Cosmic Microwave Background and Cosmic Infrared Background
Seoul National University（首尔大学）；Institute for Data Innovation in Science, Seoul National University（首尔大学数据创新科学研究所）；The Pennsylvania State University（宾夕法尼亚州立大学）；School of Physics, Korea Institute for Advanced Study（韩国高等科学研究院物理学院）；Academia Sinica Institute of Astronomy and Astrophysics (ASIAA)（中央研究院天文及天文物理研究所）；SNU Astronomy Research Center, Seoul National University（首尔大学天体物理学研究中心）
