研究亮点与新闻

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Machine learning recovers H II morphology during reionization

The epoch of reionization (EoR) is a unique period of time in cosmic evolution, during which ultraviolet (UV) and X-ray photons emitted from the first luminous objects (e.g. first stars and galaxies) ionize hydrogen atoms first in the surrounding intergalactic medium (IGM) and form bubbles of H II regions, and eventually these H II bubbles fill the whole Universe. The bubble size distribution of ionized hydrogen regions probes the information about the morphology of H II bubbles during the reionization, and it can be derived from the tomographic imaging data of the redshifted 21cm signal.

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Gas Evolution in the Early Universe Revealed with Keck

Over the past few decades, astronomers have studied the process of gas accretion that drives the formation of stars and galaxies within dark matter halos. People have established a theoretical paradigm, which envisions galaxies fed by cool ‘streams’ of gas, linked to the surrounding circumgalactic medium (CGM) and intergalactic medium (IGM) by a web of cosmic filaments. Despite the general agreement among theorists, fundamental questions are yet to be solved and tested empirically. Due to their extremely low densities, the emission of CGM and IGM are very faint with very low surface brightness. Fortunately, recent development of more advanced instrumentations allows astronomers to see the low-surface brightness IGM emission for the first time.

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CNSA officials visited Tsinghua to discuss the HUBS project

The Deputy Director of the Chinese National Space Administration (CNSA), Mr. WU Yanhua, led a delegation to visit Tsinghua University on Dec. 13, 2019, specifically to discuss a proposed China-led international space project, known as the Hot Universe Baryon Surveyor (HUBS), for X-ray astronomy. Accompanied by Vice President YOU Zheng, Deputy Director Wu and other CNSA officials visited the Low-Temperature Detector (LTD) Laboratory, which is housed in the Department of Astronomy, and learned about the status of detector development for HUBS, which is funded by the China Natural Science Foundation.

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INQUIRIES OF HEAVEN: Exoplanets & Extraterrestrial Life

The first lecture of "INQUIRIES OF HEAVEN" forum of Tsinghua University Public Lecture series, "Exoplanets & Extraterrestrial Life", took place in the auditorium of Tsinghua University on the evening of November 15, 2019, as scheduled. Prof. LIN Chao, a famous astrophysicist, Prof. ZHU Ting, School of life, Tsinghua University, and MS. HAO Jingfang, a popular science fiction writer who won the Hugo Award, were invited as guests. Prof. MAO Shude, head of the Department of Astronomy, Tsinghua University, was the host. Although the weather was cold, the atmosphere was very active. More than 500 people attended the lecture, and more than 3800 people listened to the lecture online through the live network platform.

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Constraining nature of ultra-light dark matter particles with 21cm forest

The ultra-light scalar fields can arise ubiquitously, for instance, as a result of the spontaneous breaking of an approximate symmetry such as the axion and more generally the ultra-light particles (ULPs). In addition to the particle physics motivations, these particles can also play a major role in cosmology by contributing to dark matter abundance and affecting the structure formation at sub-Mpc scales.

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Recruitment procedures for PhD students 2020

The recruitment procedures and admission list for DoA PhD students in 2020 can be found here.

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