科学研究
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2024.02.28
Weak Lensing Without Shape Noise
Weak gravitational lensing imprints a coherent distortion onto the observed shapes of distant galaxies. At the image level, this gravitational shear degenerates with the intrinsic shape of galaxies, and the weak lensing signal-to-noise from an individual galaxy is of order 0.01. I will describe Kinematic Lensing, a new technique combining imaging and galaxy kinematics to measure weak lensing wi...
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2024.01.12
Ultra-compact dwarf galaxies caught in the act of transformation
In the past two decades, systematic studies have revealed hundreds of ultra-compact dwarf galaxies (UCDs) in the nearby Universe. While similar in appearance to massive globular clusters, the detection of extended stellar envelopes, complex star formation histories, elevated mass-to-light ratio, and supermassive black holes suggest that some UCDs are remnant nuclear star clusters of tidally-str...
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2024.01.11
Witnessing the Birth of Planets: The Structure and Chemistry of Planet-Forming Disks
To date, there are more than 5000 exoplanets discovered in our neighborhood, showcasing a remarkable diversity in planetary system architectures. Unraveling the planet formation process, as well as the origin of this diversity, requires a comprehensive understanding of their birth sites - the dusty and gas-rich disks orbiting around young stars. ALMA’s unprecedented spatial resolution and sens...
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2024.01.09
Exploring the new high-redshift frontier with the James Webb Space Telescope
The advent of the James Webb Space Telescope (JWST) has brought the study of early galaxy formation to a new level. Shortly after it began its scientific operation, JWST revealed a large number of candidate galaxies at redshift (z) greater than 11 when the universe was less than ~420 million years old, some of which could even be at z ~ 20 (age of the universe ~180 million years). This was comp...
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2024.01.09
Deciphering Galaxy Quenching: Insights from the Multiphase Circumgalactic Medium
In the galactic ecosystem, the circumgalactic medium (CGM) is a massive baryon reservoir orchestrating baryonic inflows and outflows, shaping galaxy formation and evolution. Of profound significance is the quenching of cosmic star formation since cosmic noon, pivotal in unraveling present-day galaxy characteristics, yet its driving force remains uncertain. Characterizing and modeling the CGM em...
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