宇宙黎明和再电离信号探测是目前运行以及即将建成的低频射电阵列(如平方公里阵列square kilometer array, SKA)的首要科学目标之一。红移z=6~27时期的HI超精细能级跃迁产生的21 cm辐射是进行宇宙黎明和再电离时期探测的最直接而有效的...宇宙黎明和再电离信号探测是目前运行以及即将建成的低频射电阵列(如平方公里阵列square kilometer array, SKA)的首要科学目标之一。红移z=6~27时期的HI超精细能级跃迁产生的21 cm辐射是进行宇宙黎明和再电离时期探测的最直接而有效的工具,通过探测HI的21 cm信号可以描绘出宇宙第一代发光天体的产生和形成过程,从而研究宇宙从黑暗走向光明的历史。主要介绍近年来宇宙黎明和再电离探测方向的相关研究进展,讨论了在宇宙黎明和再电离探测时期探测中关于前景去除、数据处理方法等相关问题,以及低频射电望远镜在全天总功率测量、功率谱测量方面的研究进展。展开更多
Following recent Cosmic Microwave Background (CMB) observations of global spatial flatness, only two types of viable cosmological models remain: inflationary models which almost instantaneously attain cosmic flatness ...Following recent Cosmic Microwave Background (CMB) observations of global spatial flatness, only two types of viable cosmological models remain: inflationary models which almost instantaneously attain cosmic flatness following the Big Bang;and non-inflationary models which are spatially flat from inception. Flat Space Cosmology (FSC) is the latter type of cosmological model by virtue of assumptions corresponding to the Hawking-Penrose conjecture that a universe expanding from a singularity could be modeled like a time-reversed black hole. Since current inflationary models have been criticized for their lack of falsifiability, the numerous falsifiable predictions and key features of the FSC model are herein contrasted with standard inflationary cosmology. For the reasons given, the FSC model is shown to be superior to standard cosmology in the following eleven categories: Predictions Pertaining to Primordial Gravity Waves;Cosmic Dawn Early Surprises;Predicting the Magnitude of CMB Temperature Anisotropy;Predicting the Value of Equation of State Term w;Predicting the Hubble Parameter Value;Quantifiable Entropy and the Entropic Arrow of Time;Clues to the Nature of Gravity, Dark Energy and Dark Matter;The Cosmological Constant Problem;Quantum Cosmology;Dark Matter and Dark Energy Quantitation;Requirements for New Physics.展开更多
探测中性氢原子的21 cm信号对于理解宇宙最初十亿年的演化历史至关重要,同时可以为研究宇宙的膨胀历史、暗物质与暗能量的性质,以及结构形成与演化提供重要的宇宙学探针.平方公里阵列射电望远镜(Square Kilometre Array,SKA)是一个国际...探测中性氢原子的21 cm信号对于理解宇宙最初十亿年的演化历史至关重要,同时可以为研究宇宙的膨胀历史、暗物质与暗能量的性质,以及结构形成与演化提供重要的宇宙学探针.平方公里阵列射电望远镜(Square Kilometre Array,SKA)是一个国际大科学工程项目,建成后将成为世界上最大的射电望远镜.在未来的几十年内,SKA将推动21 cm宇宙学迈入一个新时代.展开更多
文摘宇宙黎明和再电离时期探测是目前宇宙学最前沿科学研究方向之一.对这一时期的直接探测只能依赖于观测来自这一时期红移后的中性氢21 cm信号,其3种主要探测方式之一是21 cm信号全天总功率测量.在此回顾已有和正在计划中的探测宇宙黎明和再电离时期的低频全天总功率测量实验及其进展,包括地面射电望远镜如BIGHORNS1、EDGES2、LACE3、LEDA4、MIST5、REACH6、SARAS73、SCI-HI8、PRIZM9以及空间低频总功率相关实验如DARE10、DAPPER11、FARSIDE12、鸿蒙计划.其中,EDGES实验是目前唯一声称观测到疑似宇宙黎明信号的实验,然而其实验结果与标准宇宙学模型(ΛCold Dark Matter,ΛCDM)有不符之处.如果该探测结果被证实,那么这将是人类第1次探测到宇宙黎明和再电离信号,从而填补宇宙演化历史的空白.
文摘Following recent Cosmic Microwave Background (CMB) observations of global spatial flatness, only two types of viable cosmological models remain: inflationary models which almost instantaneously attain cosmic flatness following the Big Bang;and non-inflationary models which are spatially flat from inception. Flat Space Cosmology (FSC) is the latter type of cosmological model by virtue of assumptions corresponding to the Hawking-Penrose conjecture that a universe expanding from a singularity could be modeled like a time-reversed black hole. Since current inflationary models have been criticized for their lack of falsifiability, the numerous falsifiable predictions and key features of the FSC model are herein contrasted with standard inflationary cosmology. For the reasons given, the FSC model is shown to be superior to standard cosmology in the following eleven categories: Predictions Pertaining to Primordial Gravity Waves;Cosmic Dawn Early Surprises;Predicting the Magnitude of CMB Temperature Anisotropy;Predicting the Value of Equation of State Term w;Predicting the Hubble Parameter Value;Quantifiable Entropy and the Entropic Arrow of Time;Clues to the Nature of Gravity, Dark Energy and Dark Matter;The Cosmological Constant Problem;Quantum Cosmology;Dark Matter and Dark Energy Quantitation;Requirements for New Physics.
文摘探测中性氢原子的21 cm信号对于理解宇宙最初十亿年的演化历史至关重要,同时可以为研究宇宙的膨胀历史、暗物质与暗能量的性质,以及结构形成与演化提供重要的宇宙学探针.平方公里阵列射电望远镜(Square Kilometre Array,SKA)是一个国际大科学工程项目,建成后将成为世界上最大的射电望远镜.在未来的几十年内,SKA将推动21 cm宇宙学迈入一个新时代.
