 The spinning of Sagittarius A* is vital to characterize the supermassive black hole and it is crucial in testing the “cosmic censorship conjecture” and “no hair theorem” of black hole spacetime in Einstein's general relativity. Previous studies have shown that the spin of Sagittarius A* could be measured within 1 percent relative uncertainty by timing radio signals from pulsars. However, these measurements depend on the discovery of a pulsar in a very compact orbit of less than half a year, a challenging prospect from observation. In order to alleviate the problem, a recent study, carried out by Zexin Hu and Prof. Lijing Shao from KIAA, provides a novel method of combining the observation of two pulsars with larger orbital periods in the Galactic Center to precisely measure the spin of Sagittarius A*. The work has been published in the journal Physical Review Letters.
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 In 1936, astronomers saw a puzzling event in the constellation Orion: the young star FU Orionis (FU Ori) became hundreds of times brighter in a matter of months. At its peak, FU Ori was intrinsically more than 100 times brighter than our Sun. However, unlike an exploding star, FU Ori has declined in luminosity only slowly since then. In the subsequent decades, this brightening of FU Ori became understood as a large, sustained burst of accretion onto a forming star.
Originally deemed to be a unique case among stars, FU Ori exemplifies a class of young, eruptive stars that undergo dramatic increases in brightness. These accretion bursts are thought to play an important role in the physical and chemical evolution of the forming star and the planet-forming disk.
Now, a team of astronomers, including Prof. Gregory Herczeg of the Kavli Institute for Astronomy and Astrophysics at Peking University, has wielded NASA's Hubble Space Telescope's uniquely powerful ultraviolet capabilities to uncover the interactions between the stellar surface of FU Ori and its accretion disk. "Most stars must go through periods of such strong accretion, either very early in its formation or as an outburst," said Prof. Herczeg. "Our measurements of how the gas accretes onto the star help us to understand the processes that form the star and how those processes shape the planet-forming environment." These results were reported in the October issue of Astrophysical Journal Letters.
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 Astronomers using the U.S. National Science Foundation Green Bank Telescope reveal new process of star formation, challenging existing models.
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 For the first time, groundbreaking research spearheaded by Professor Li-Xin Li from the Kavli Institute for Astronomy and Astrophysics at Peking University, alongside his Ph.D. student Jia-Yin Shen, and Associate Professor Cheng Peng from the Kavli Institute for Theoretical Sciences at the University of Chinese Academy of Sciences, delves into the dynamics of multi-boundary spacetimes formed by gluing multiple bulk spacetimes along a shared interface. Their innovative work has been featured in the famous journal Physical Review Letters.
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 Beneath the apparent diversity and complexity in morphology, galaxies show underlying simplicity and have universally bimodal distributions of normalized specific angular momentum of stars, according to a study led by KIAA/PKU researchers Dr. Bitao Wang and Prof. Yingjie Peng. These two prevailing galaxy populations, dominated respectively by chaotic random motion and ordered bulk rotation, are shown to have experienced contrasting evolutionary histories. The work is published in the Sept 27 issue of Nature Astronomy.
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 Recently, a team of astrophysicists, including Dr. Haoxiang Lin and Prof. Zhuo Li from the Kavli Institute for Astronomy and Astrophysics (KIAA), Peking University and the GECAM (The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor) team led by Prof. Shaolin Xiong from Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, has two groundbreaking papers about GRB 221009A, recently published in The Astrophysical Journal Letters, shedding new light on the physics of GRB jets.
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