报告讲座
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格物致理56期：第一代恒星和宇宙再电离
宇宙再电离时代（EoR）是大爆炸宇宙学模型预言宇宙必然经历的一个时期，宇宙再电离过程涉及宇宙早期恒星和星系的形成与演化、中性星系际介质电离和加热等多种天体物理过程。本报告将介绍本人在该领域已完成的相关工作，包括EoR时期的GRB和DLA中的第一代恒星信号、高红移类星体的近邻21厘米信号、宇宙早期的星系形成模型、双星系统对宇宙再电离的贡献、EoR的X射线源模型对21厘米统计性质的影响、以及21厘米信号与其他辐射背景的互相关。
发布者： 发布时间：2023-12-15 09:40:01 -
The Chang-Yun Fan cosmic ray series 第7期:Probing Galactic and Extragalactic Cosmic Ray Factories with high energy gamma -rays
Extraterrestrial gamma rays tell us about the most energetic and violent phenomena in the Universe. The respective research area - Gamma Ray Astronomy - addresses a broad range of nonthermal high-processes of particle acceleration, propagation, and radiation on all astronomical scales, from compact neutron stars and black holes to large-scale cosmological structures. Gamma-ray studies cover a wide range of areas linked to the physics and astrophysics of SNRs, Star Formation,Magnetospheres of Pulsars and Black Holes, physics of relativistic outflows - Pulsar Winds, AGN jets, GRBs, etc.
发布者： 发布时间：2023-12-13 09:18:26 -
射电望远镜及极弱信号检测
射电望远镜极大地扩展了对电磁波的观测范围，射电天文学是第一个不在可见光波段的分支，因此也是探索最广泛的学科之一。天文学上的很多天体物理学，都涉及对更多电磁波段的观测。介绍极弱信号测量装置的研制，其可作为大型通讯设备选址、无线电干扰查找、微波巡视、卫星信号监测、无线电定位、空间天气、大气水汽监测等方面的科研设备。
发布者： 发布时间：2023-12-12 10:44:05 -
格物致理55期：贝特/规范对应关系及其应用
贝特拟设方程最早由贝特提出用来对角化海森堡自旋链，而该方程组的解将决定了系统的本征值和本征态。与此同时，人们发现该方程组在特定超对称规范场论中也可作为真空方程出现，形成了最早的贝特/规范对应关系。在本次报告中，我们将依次回顾贝特拟设方程、超对称规范场论以及他们的对应关系，并包含最近我们对该对应关系一些新的理解。作为贝特/规范对应关系的一个应用，我们将介绍如何利用场论中的严格解来解决贝特拟设方程解的完备性问题。
发布者： 发布时间：2023-11-24 12:04:16 -
格物致理54期：星系-暗物质晕关系与机器学习
Energy Spectrum of Solar Energetic Electron Events
发布者： 发布时间：2023-11-20 09:50:20 -
Stellar Activity and Exoplanets
Stellar magnetic activity and exoplanets are currently among the most promising research topics in modern astronomy. The exoplanets and their host stars are always closely intertwined with each other during their lifetimes and therefore also during the processes of planet detection and characterization. Due to limit of observing conditions and lack of key data accumulation, we only know a little information about the modes and regularities of stellar magnetic activities at various stellar evolutionary stages, which prevents to include magnetic field into stellar structure and evolution model in a proper way even if it is known that magnetic field almost exists in all stages of stellar evolution. On the other hand, observations for exoplanets can help to seek habitable planets so as to answer the eternal puzzle “Are we alone?”.
发布者： 发布时间：2023-11-15 12:40:02