Research
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2024.05.14
Gravitational radiation from oscillations of ultracompact stars
By analytically solving the Teukolsky gravitational wave equation for the spacetime of an ultracompact star of constant density, we derive exact and simple formulae that completely describe weakly damped oscillations trapped inside such stars. No similar complete analytic solution was known before, despite several attempts to find it. Our solution is cast in terms of the quasi normal modes of o...
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2024.05.10
Biases and uncertainties in quantifying morphology of galaxies at high redshifts with JWST
Observations of high-redshift galaxies with unprecedented detail have now been rendered possible with JWST. However, accurately quantifying their morphology remains uncertain due to potential biases and uncertainties. To address this issue, I used a sample of 1816 nearby DESI galaxies to compute artificial images of galaxies of the same mass located at high redshifts and observed at rest-frame ...
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2024.05.09
The sample and mass loss rate of red supergiants in M31 and M33
Red supergiants are important contributors to interstellar medium through massive wind. Due to serious interstellar extinction, the complete sample of RSGs is extremely difficult to obtain in our Galaxy. As two of the largest spiral galaxies in the Local Group, M31 and M33 can serve as a reference to analyze the global contribution of RSGs to the galactic medium. By using evident branching of...
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2024.05.08
Dark Matter Halo and its Structure, Assembly, and Clustering
Dark matter halos are the major composition of the cosmic structures in our Universe and, therefore, play a central role in studying galaxies and cosmology. In cosmological N-body simulations, dark matter halos can be investigated from three perspectives: their structures, assembly histories, and spatial clustering. This talk will focus on our recent work on this topic. In the first part, I wil...
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2024.04.26
Research on the Structure, Chemistry and Kinematics of the Milky Way Based on the Large-scale Sky Surveys
With the advent of massive large-scale sky surveys, such as, the SDSS for photometry, the LAMOST for spectroscopy, and Gaia for astrometry, we are entering a golden era of Galactic studies and precise multi-dimensional information (e.g., 3D position, 3D velocity, chemical element abundance ratios, and stellar age) is now available for some huge samples of stars in the Milky Way. Leveraging thes...
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