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2024.10.10

Probing the spacetime variation of the fine-structure constant using emission-line galaxies

<p>The Standard Model of particle physics assumes that fundamental physical constants, including the fine-structure constant alpha, are universal and constant. On the other hand, modern theories beyond the Standard Model predict or even require the variation of the fundamental constants. Recently, we developed a new method to probe the variation in alpha using narrow and strong [O III] emitting ga...</p>

2024.12.12

Trust me, I am an Astrophysics Foundation Model [EN]

<p>As datasets continue to grow, machine learning/artificial intelligence (ML/AI) has taken on an increasingly large role in scientific analyses as both a practical necessity (to handle the data volumes) but also as a way to &quot;bypass&quot; theoretical models by learning directly from the data. However, this speed, complexity, and flexibility also have proved to be one of the main challenges involved in ...</p>

2024.12.05

Multi-phase medium in galaxy groups and clusters [EN]

<p>Galaxy groups and clusters are the least massive systems where the bulk of baryons are accounted for and also the most massive systems that are gravitationally bound. They contain a wealth of galaxies sampling the broad spectra of galaxy properties, including the most massive galaxies (and probably the most massive supermassive black holes) and galaxies with the highest velocities in the univer...</p>

2024.11.28

Water chemistry of the Enceladus ocean and the habitability of icy moons [EN]

<p>Enceladus, a small icy satellite of Saturn, was found to have a subsurface water ocean and evidence of ongoing hydrothermal activity in the seafloor. The ocean water, sampled via a plume, was inferred to contain substantial levels of inorganic and organic carbon as well as ammonia. However, there are very few constraints on the availability of other bio-essential nutrients, including phosphorus...</p>

2024.11.21

A new picture of active galactic nuclei disks [EN]

<p>The current model of accretion disks, that of Shakura and Sunyaev (1973) asserts that such disks are geometrically thin, and are prone to a number of instabilities. One such instability is that of fragmentation due to self-gravity at radii larger than a few hundred black hole gravitational radii, which would limit the mass accretion rate to be well below that observed to occur. Recent GIZMO (La...</p>

2024.11.14

Einstein Probe: starting to reveal a deeper and clearer view of the dynamic X-ray universe [EN]

<p>The Einstein Probe (EP, renamed 天关 in Chinese last week), launched on January 9th, 2024, is a space X-ray observatory of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. It is detecting high-energy transient and variable sources in the X-ray band with better sensitivity and spatial resolution by at least one order of magnitude than the other operating wide-field monito...</p>

2024.11.07

Cosmic evolution of the physical conditions for star and star cluster formation

<p>Recent observations from ALMA and JWST have revealed the complex and turbulent nature of galaxies at high redshift, during the epoch of formation of globular clusters. The emergence of large disks at cosmic dawn (z &gt; 10) and the almost ubiquity of massive star forming clumps at cosmic noon (z~2) question the formation scenarios of globular clusters. Although gravitational lensing pushes the obs...</p>

2024.10.31

Current and future characterization of small exoplanet atmospheres from ground and space

<p>Planets between the size of Earth and Neptune, also known as sub-Neptunes, pose a conundrum. They are absent in the solar system, but more than half of all Sun-like stars in the Galaxy host a sub-Neptune interior to 1 au. Although the number of sub-Neptunes atmospheres probed so far has been very low, a major breakthrough in exo-atmospheres science is happening right now thanks to the increased...</p>

2024.10.24

Stellar physics and population in the open cluster lab (英文报告)

<p>Open clusters provide an ideal laboratory for testing and calibrating our understanding of stellar physics and single stellar population. In this talk, I will discuss how astronomers use open clusters as a well-defined single population of stars to study the Milky Way disk and stellar evolution. Additionally, I will explore how open clusters can be used to validate pipeline results from large p...</p>

2024.10.17

Hypervelocity stars: energetic guys “kissed” by massive black holes

<p>The so-called Hypervelocity stars (HVSs; with velocities even greater than 1000 km/s) were first predicted from the theoretical arguments of Hills (1988), and attributed to be the result of tidal interaction between a close stellar binary system and a supermassive black hole (SMBH) in the Galactic center, commonly referred to as the “Hills mechanism”. HVSs or High-Velocity stars (HiVels) can ...</p>