Signing Ceremony of MUST Precision Optoelectronic System R&D Base Held in Jiangyin
On May 7, 2023, the precision optoelectronic system research and development base of MUST, Tsinghua University, signed a contract in Jiangyin. Guo Yong, Vice Secretary of the Party Committee of Tsinghua University, Xu Feng, member of the Standing Committee of the Wuxi Municipal Committee and Secretary of the Jiangyin Municipal Committee, Zheng Yongping, Dean of the Wuxi Applied Technology Research Institute of Tsinghua University, Niu Ben, Director of Domestic Cooperation Office of Tsinghua University, Cai Zheng, MUST Project Manager and Associate Chair of the Department of Astronomy, Tsinghua University, Huang Lei, MUST Project Chief Engineer, and Assistant Dean of the Department of Precision Instruments, and Jiangyin municipal leaders Wu Liping, Chen Hanjie, Cao Xinghua, and Qi Jun attended the signing ceremony. !(https://must.astro.tsinghua.edu.cn/admin(http://localhost:1337/uploads/_63c4195b11.png) Xu Feng expressed a warm welcome to Guo Yong and his delegation. He said that Tsinghua University is a world-renowned institution of higher education with a long history and profound background, and has made outstanding contributions to the country's construction and development, social civilization, and progress. Jiangyin is the flag of county-level economic development in the country, and is currently accelerating the construction of "Science and Technology Innovation Jiangyin". The project will be settled in the Xiake Bay Science City, which is a high-quality development, high-quality growth pole, vibrant innovation source, beautiful ecological area, and digital new height, which Jiangyin key builds. Xu Feng stated that the Jiangyin Municipal Party Committee and the government will fully support the project's landing, provide all convenience for the project construction, and sincerely invite Tsinghua University to establish more cooperation with Jiangyin, and create a new highland of school and land cooperation and a new model of political and research cooperation. Guo Yong stated that Jiangyin is blessed with both fine people and excellent geographical location, and the Jiangyin Municipal Party Committee and Government have left a deep impression on everyone by focusing on technological innovation to promote high-quality economic and social development. He pointed out that in 2021, Tsinghua University released the "Tsinghua University 2030 Innovation Action Plan", which focuses on optimizing disciplinary layout, strengthening disciplinary construction, intensifying basic research and tackling key core technologies, and prosperous development of humanities and social sciences. The Wide-Field Survey Telescope Project signed this time is an important part of it. Guo Yong hopes that both sides will continue to deepen and expand the breadth and depth of university-local cooperation, steadily promote the construction of large scientific facilities, and provide strategic support for serving the country's technological independence and self-improvement. !(https://must.astro.tsinghua.edu.cn/admin(http://localhost:1337/uploads/2_67e3d0409d.png) Deep space exploration is the "blue ocean" for breakthrough discoveries in the field of basic science. In the next decade, the development of deep space exploration will show further accelerated trends. However, in the extremely important fields of optics and infrared, the new generation of wide-field survey telescopes has yet to be completed internationally. In view of this, Tsinghua University has taken the lead in launching the important layout of constructing MUST, planning to build a large aperture, wide field of view, and high-efficiency spectral telescope. This facility belongs to the internationally leading large scientific installation, and is expected to achieve major fundamental and original breakthroughs in frontier directions such as dark energy evolution, nature of dark matter, and extrasolar planets, and obtain first-class international results. The MUST team will rely on the Wuxi Applied Technology Research Institute of Tsinghua University to establish the "Precision Optoelectronic R&D Center." They will focus on topics such as base construction, technology research and development, and outcome transfer and transformation, closely related to the large-scale optoelectronic equipment construction of MUST. They will accelerate the gathering of talents in the aerospace technology and high-end optical equipment manufacturing fields, and create a world-class scientific frontier R&D platform and application base to foster a good environment for scientific and technological innovation. Source: Wuxi Applied Technology Research Institute of Tsinghua University
The MUST scientific team published a paper on Science as the first author. Direct Imaging of Gas Recycling around a Massive Galaxy 11 Billion Years Ago
Galaxies are the birthplace of most stars and black holes. However, scientists are still debating, how galaxies accrete the fuel to sustain their growth and how they in turn pollute their environment with elements heavier than helium. The scientific team led by MUST project manager Cai Zheng at Tsinghua University has now directly observed the neighborhood of a massive galaxy in the early Universe. They find that the gas all around the galaxy is enriched with heavy elements, which means it has been polluted by the galaxy itself and by embedded satellite galaxies. Furthermore, this gas is spiraling onto the massive galaxy, fueling further star formation. !(https://must.astro.tsinghua.edu.cn/admin(http://localhost:1337/uploads/202305070957291_ad1a7fa44f.jpg) According to the first models of galaxy formation, gas fell isotropically onto dark matter halos, was shock-heated to very high temperatures (millions of degrees), and subsequently cooled to form stars in the emerging/growing central galaxy. However, it is now clear that this so-called ‘hot-mode’ accretion accounts for only a small fraction of the fuel powering the violent star formation in massive galaxies in the early universe. Instead, cosmological hydrodynamical simulations indicate that a ‘cold-mode’ accretion (thousands of degrees) onto galaxies occurs along filaments. This accretion process is more efficient in transporting gas down to the galaxy, providing a natural mechanism to sustain the observed large star-formation rates. In turn, stars pollute their surrounding environment with elements heavier than helium, globally referred to as “metals”. The most energetic phenomena (supernova explosions) are even able to generate galactic outflows, enriching the circumgalactic gas. Recent cosmological simulations indicate that this metal-enriched gas ejected by the galaxy could fall back, resulting in a further supply mechanism to sustain intense star-forming activity. Therefore, a massive galaxy will both recycle its metal-polluted gas and use pristine, inflowing gas, which should have a non-zero metal content. However, direct observational evidence for the presence of such recycled inflows had not been obtained so far. An international team of astronomers has therefore targeted a massive system in the early universe, to get a first glimpse on how such galaxies accrete their gas. The chosen system, MAMMOTH-1, can be observed at an epoch corresponding to 11 billion years ago. It is a galaxy group embedded in large-scale cold circumgalactic gas, which shines bright in Lyman-alpha emission from hydrogen. With data from the Keck Cosmic Web Imager (KCWI, Keck II telescope) and narrowband imaging from the Subaru telescope, the team detected circumgalactic line emission in hydrogen, helium, and carbon extending for 300 000 light years. An analysis of the line ratios allowed the team to obtain the gas properties throughout the halo. The results show that the circumgalactic gas has already been enriched to solar metallicity, which is quite surprising at this early cosmic epoch. Further, the KCWI data allowed the team to analyse the kinematics of the emitting gas in the observed region. A detailed comparison of the data with cosmological simulations and an analytical model can explain the observed velocity patterns, which are most likely due to recycled inflow gas. The kinematic model indicates that the gas accretion is occurring at a rate of about 700 solar masses per year, much more than the measured star-formation rate of the central galaxy (81 solar masses per year). The metal-enriched inflow could thus fully sustain the intense star formation in the massive galaxy. “Our observations give a first hint that recycled inflows might be an ubiquitous supply mechanism for massive star-forming galaxies in the early universe”, remarks Zheng Cai of Tsinghua University, the Principle Investigator of this study and corresponding author of this paper. In addition, the team also found that satellite galaxies in this galaxy group have the same motion as the circumgalactic gas, indicating that they are embedded in the inspiraling streams. Therefore, these satellite galaxies could interact with and pollute the circumgalactic gas. “This makes the galaxy-gas ecosystem even more complex, but also it makes more plausible that gas recycling is an important ingredient,” adds Shiwu Zhang of Tsinghua University and first-author of the study. In future, one could have a lot more sensitive observations of circumgalactic emission to give us more insights on the intricate ecosystem of galaxies. The upcoming exquisite datasets, such as from the MUSE/VLT, KCWI instruments, and JWST, allows astrophysicists to directly study the circumgalactic gas in detail and thus better understand the physical processes governing the gas cycle around galaxies. Source: Official website of Tsinghua University. official website of Department of Astronomy, Tsinghua University
Spring Team Building 2023 for Center for Astronomy Technology, Tsinghua University in Fenghuangling
In order to enrich the team's leisure activities, enhance communication and exchange among members, and establish a team atmosphere of mutual understanding and trust, the Center for Astronomy Technology, Tsinghua University launched a mountain climbing activity at Fenghuangling (Beijing) as the team building on April 27, 2023. And a total of 25 members from the MUST team participated in the activity. #### ![Group photo of the Center for Astronomy Technology, Tsinghua University](https://must.astro.tsinghua.edu.cn/admin(http://localhost:1337/uploads/20230428134625_757ece5fce.jpg) #### ![Icebreaker for team members before the climb](https://must.astro.tsinghua.edu.cn/admin(http://localhost:1337/uploads/202304281348584_e698674e68.jpg) ![group photo of climbing the top](https://must.astro.tsinghua.edu.cn/admin(http://localhost:1337/uploads/20230428134645_fc7498d08b.jpg) During the mountain climbing, everyone had in-depth communications about work and life-related questions and experiences, achieving both physical fitness and the happiness and knowledge gained along the way. We encouraged and helped each other, and eventually reaching the summit. Collaborative teamwork helps us go further. The activity not only promoted the spirit of challenging oneself, forging ahead, and working together for the MUST team, but also advocated for a positive and healthy lifestyle, and “work healthily for 50 years for the country” with practical actions. The Center for Astronomy Technology, Tsinghua University will continue to strengthen team cohesion, improve team execution, and optimize team communication through various activities, striving to push the MUST project forward as soon as possible!
MUST(MUltiplexed Survey Telescope)
In the past decade, five Nobel prizes were awarded to the field of astronomy and astrophysics, and the whole field shows rapid development. At present, astronomy has entered a new era of multi-messengers and big data, our observations and understanding of the universe will achieve great leap forward in depth and breadth, and may reveal new laws of the universe. Under the leadership of Tsinghua University, we plan to build a MUltiplexed Survey Telescope (MUST) in mainland China. After its completion in about a decade, its spectroscopic survey capability will be more than 10 times higher than the current level. In combination with the future multi-wavelength imaging surveys, MUST is expected to make breakthroughs in many fields including the nature of dark matter and dark energy, gravitational wave cosmology, galaxy formation and evolution, enabling China to be a potential leader in the field of ground-based astronomical observations. In addition, MUST will derive great progress in advanced optics, precision machinery, high-performance detectors and other fields. We look forward to cooperating with you!
Explore the nature of dark matter, probe the origin of dark energy, and depict a dynamic universe.
About the project, about the team, more information.
- Scientific ObjectivesThe main scientific goal of MUST is to create a more precise cosmology model. To achieve this, MUSTT will perform surveys of large-scale structures at high redshifts to better understand the origins and evolution of dark energy, inflation models, and neutrino mass. MUST plans to conduct redshift surveys of galaxies on the non-linear scale to understand the galaxy-halo connection better. MUST will also utilize multiple observational probes, ranging from galaxies to stars, to shed light on the nature of dark matter.➔
- MUST TeamThe MUST team consists of academic and industry experts who are committed to exploring cosmology, galaxy evolution, exoplanets, and other relevant fields in astronomy.➔
- Site InformationThe MUST telescope will be built at Point A (longitude 93°54'00" east, latitude 38°36'50" north) of C Zone, Saishiteng Mountain in Lenghu Town, Mangya City, Haixi Mongolian-Tibetan Autonomous Prefecture, Qinghai Province, China, which is the "Lenghu Astronomical Observation Base."➔