科学研究
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2024.09.20
Unveiling the 70-year mystery of the nature of carbon-deficient red giants
Weak G-band stars, or carbon-deficient red giants (CDGs), characterised by weak or absent G-band absorption of the CH molecule driven by low carbon abundances, have remained mysterious for decades. Here, we present a significant increase in the known CDG population identified through systematic spectroscopic surveys. This expanded sample confirms their rarity (
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2024.09.19
Dynamic and Untamed: the early life of circumstellar disks
Circumstellar disks as young as 0.5 Myr bear gaps and rings as tentative planet signposts, which aligns with accumulating evidence of early planet formation. However, such young disks are poorly understood both observationally and theoretically. They are likely affected by the star formation environment becoming warped or eccentric. The disk flow can become peculiar, and various instabilities f...
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2024.09.13
Identifying the Galactic Substructures in 5D Space Using All-sky RR Lyrae Stars in Gaia DR3
Motivated by the vast gap between photometric and spectroscopic data volumes, there is great potential in using 5D kinematic information to identify and study substructures of the Milky Way. We identify substructures in the Galactic halo using 46,575 RR Lyrae stars (RRLs) from Gaia DR3 with the photometric metallicities and distances newly estimated by Li et al. (2023). Assuming a Gaussian prio...
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2024.09.12
Supermassive black holes in the Universe
Supermassive black holes are extensively discussed in this talk: 1) cosmic evolution of SMBHs; 2) masses and spins; 3) SMBH binaries and nano-Hz gravitational waves; 4) Satellite black holes around SMBH; 5) new opportunity of SMBH research in the JWST and VLTI era.BIOJianming Wang is astrophysics professor in IHEP. He got PhD in USTC in 1995 and originally from National University of Defense Te...
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2024.09.12
Tensions on small scales: Too many galaxy-galaxy strong lenses in galaxy clusters?
In the standard cosmological model, the matter content of the Universe is dominated by cold dark matter (CDM), collisionless particles that interact with ordinary matter (baryons) only through gravity. Gravitationally bound dark-matter halos form hierarchically, with the most massive systems growing through mergers of smaller ones. As structure assembles in this fashion, large dark-matter halos...
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