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2023.03.16

Microphysical and non-thermal processes in the circumgalactic medium: turbulence, magnetic fields and cosmic rays

<p>Multiphase gas structure is ubiquitous in our universe. Recent observations suggest that large quantities of cool (10^4 K) gas are detected in the circumgalactic medium (CGM) of galaxy halos, which extends up to a few times of galactic virial radius. In addition, warm gas at a few 10^5 K is found to be tightly associated with the star-forming galaxies, but not the quenched ones. However, the or...</p>

2023.03.02

The variation of the stellar initial mass function (IMF) with metallicity and time

<p>The stellar IMF is one of the most important astrophysical distributions and plays vital role in galactic astronomy. Both constant and variable IMFs across different environments have been claimed despite a large number of theoretical and observational efforts. However, the measurement of the IMF in Galactic stellar populations has been limited by the relatively small number of photometrically ...</p>

2023.02.23

Solar-like Oscillations: Past, Present, & Future

<p>The analysis and interpretation of stellar oscillations ---asteroseismology --- permits direct observational examination of stellar interiors. In particular, low-degree p-modes, excited through the same&nbsp;stochastic convective mechanism as in our Sun, permit us to draw&nbsp;inferences about the global properties, interior structures, rotational&nbsp;dynamics, and evolutionary fates of field stars. Space-ba...</p>

2022.12.29

Cosmology with 3D maps of the Universe

<p>The spatial clustering of large-scale structures (LSS) offers insights into the expansion history of the Universe and the growth of structures, and are foreseen to tackle the mysteries of the dark energy and dark matter. Precise cosmological constraints with clustering measurements require the 3-D positions (2-D angular position and redshift) of numerous tracers, and a large sample volume. To t...</p>

2022.12.27

Universe seen through weak gravitational lensing

<p>We are facing an exciting era of discovering the nature of dark matter and dark energy with upcoming large-scale surveys, such as Chinese Survey Space Telescope (CSST), Rubin, and Euclid. One of the major analysis methods of the surveys, weak lensing (WL), uses the shape distortion of background sources for detecting the foreground matter distribution. It is a powerful method for studying dark ...</p>

2023.01.04

Mapping Interstellar Magnetic Field Strength in the Era of FAST, FASTA, and SKA

<p>Magnetic field is one of the most important physical quantities regulating the evolution of interstellar medium and star formation in the Milky Way. Despite enormous surveys using techniques of dust polarization, Faraday rotation, and synchrotron polarization to reveal the magnetic field structure of the Milky Way, none of the techniques can give accurate magnetic field strength. Zeeman effect ...</p>

2023.01.03

On Modelling Complex Systems in Astronomy

<p>Astronomy today is fundamentally different than it was even just a decade ago. Our increasing ability to collect a large amount of data from ever more powerful instruments has enabled many new opportunities. However, such an opportunity also comes with new challenges. The bottleneck stems from the fact that most astronomical observations are inherently high dimension — from “imaging” the Uni...</p>

2022.12.30

A New Era of Gravitational Wave Astronomy

<p>In this talk I will discuss promising new opportunities in gravitational wave astronomy as the sensitivity of ground-based gravitational wave detector improves, and when the space-borne detector(s) start their operation. I will use stellar-mass binary black holes, neutron stars and the so-called extreme mass-ratio inspirals as examples of these exciting developments. &nbsp;In the last part of the ta...</p>

2022.12.27

Observational signatures of compact objects in active galactic nuclei

<p>The origin of stellar-mass black hole mergers discovered through gravitational waves is being widely debated. Mergers in the disks of active galactic nuclei (AGN) represent a promising source of origin. By modelling the evolution of compact objects in AGN disks, we found that several observational signatures in gravitational wave data are only explained by the AGN channel. Beyond gravitational ...</p>

2022.11.11

Towards Precision Astrophysics for Warm Ionized Gas

<p>Understanding the physics of the interstellar medium is critical for understanding star formation and AGN feedback. Line ratio diagnostics diagrams, such as BPT diagrams, have been extensively used to study the ISM. However, their limitations hide inaccuracies of photoionization models, leading to a number of discrepant results in the literature on metallicity, abundance pattern, and correlatio...</p>