报告讲座
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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 -
The CARMENES Project
Starting in 2016 the CARMENES spectrograph (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) has conducted a 750-night survey targeting around 300 northern-sky M dwarfs. The principal science objective of CARMENES is to detect low-mass planets in the habitable zones of the targeted M dwarfs. At the same time, the CARMENES survey generates a unique data set for studies of M dwarf atmospheres, rotational and activity properties, since the spectra cover important diagnostic lines for activity studies including the Hα, sodium, the Ca II infrared triplet as well as He 10830 lines, thus providing excellent discrimination between planetary companions and stellar radial velocity "noise". In my talk I will give an overview of the CARMENES projects and the science results focussing on the work carried out at Hamburg Observatory.
发布者： 发布时间：2023-11-15 12:23:34 -
格物致理52期：宇宙中隐藏的新物理: 声速共振和宇宙学参数危机
宇宙中的新现象总是能塑造我们对早期宇宙和宇宙晚期演化的理解，本报告将介绍声速共振和宇宙学参数危机两种现象。早期宇宙中的声速共振是一种会放大原初扰动的效应，这种放大对标量和张量扰动会产生不同的效果。张量扰动表现为随机引力波谱中出现共振峰，而放大的标量扰动会触发原初黑洞的形成。对于晚期演化，我们会探讨带挠率引力在缓解宇宙学参数危机中的应用。利用不同手段对宇宙学参数进行测量时，其结果的差异导致了宇宙学参数危机。借助带挠率引力的有效场理论，我们研究了其缓解两个突出的宇宙学参数危机的潜力。而后，我们使用高斯过程对最近发布的哈勃常数数据进行模型重构，这一做法为我们提供了对精确模型的见解。这些现象将使我们更深入地理解，是什么样潜在的新物理塑造了我们的宇宙.
发布者： 发布时间：2023-11-14 16:25:34