Research Highlights and News

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PolarLight Reveals the Corona Geometry in Sco X-1

On 2022 January 1, Hua Feng's group and their collaborators reported in The Astrophysical Journal Letters a significant detection of X-ray polarization in Sco X-1 with the space mission PolarLight, which has been operating on-orbit for more than three years since its launch in 2018 October. The results help place stringent constraints on the geometry of the hot corona, and mark Sco X-1 as the second astrophysical source with a significant polarization measurement in the keV band.

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Are substructures in different components of protoplanetary disks correlated?

It is commonly believed that planets form in disks surrounding young stars, but how exactly this happens remains an outstanding question. In recent years, astronomers have made great strides in directly observing protoplanetary disks using the Atacama Large Millimeter/submillimeter Array (ALMA), located in the Atacama Desert of Northern Chile. By observing separately the emission from millimeter-sized dust particles and molecular gas, astronomers find plenty of substructures---mostly in the forms of gaps and rings along the radial direction---in both dust and gas. In some disks, the two components show substructures at the same locations. Previous studies argued that these spatially overlapping substructures are casually linked and that the primary suspect is a nearby forming planet.

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Massive Galaxies May be Crucial for the Enrichment of Cosmic Metal in the Early Universe

What are the sources of early metals and how did they enrich the intergalactic medium (IGM) are among the most crucial questions in galaxy formation. Most of the previous searches in optical wavelengths indicate that the enrichment of cosmic metals is due to low-mass galaxies that are fainter than the current detection limit. Here, we report the discovery of a galaxy associated with a strong OI absorber at redshift of 6. The galaxy has a halo mass of four hundred billion solar mass, one or two orders of magnitude more massive than that expected from modern cosmological simulations. Our observations indicate that massive galaxies may be more important in transporting metals in the intergalactic medium (IGM) than predicted by simulations.

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DoA faculty reviews the statistical distribution of exoplanets

How do planetary systems form and evolve? It is a scientific question that astronomers have long been wondering and also a key step toward understanding the origin of life and human beings on Earth. Since the discovery of the first planet orbiting around a Sun-like star outside of the Solar System in 1995 (which was awarded the Nobel Physics Prize in 2019), the number of known exoplanets has grown to over 4000. This large sample has enabled many detailed studies into the statistical distribution of planets and has sharpened our understanding of the planet formation process.

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A new movie “The Great Learning” is now being shown in theaters all over China

One of the four main characters is Prof. Zheng Cai from the Department of Astronomy. It shows his move back from the US to China, and his push, together with his collegues, to build a 6.5m telescope in China. More information is available in Chinese [link].

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Tsinghua Astronomy's 20th anniversary ceremony

On April 24th, on the occasion of the 110th anniversary of Tsinghua University, a ceremony was held to celebrate the 20th birthday of Tsinghua Astronomy, Department of Astronomy (hereafter called DoA for short) at the Chuan Shan Academy—a classic and historical place.

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