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2023.05.23

Binaries of the first stars as progenitors of compact object mergers

<p>A grand challenge for modern astrophysics is to understand star and galaxy formation in the first billion years of cosmic history. In particular, the first generation of stars born in extremely metal-poor/free primordial gas, the so-called population III (Pop III), are believed to have distinct features compared with present-day stars: They are more likely to become massive black holes due thei...</p>

2023.04.26

21cm Cosmology in the Post-Reionization Universe

<p>I will discuss some recent progress in 21cm line intensity mapping within the SKA cosmology science working group. In particular, we report the first direct detection of the cosmological power spectrum using 21cm line (2301.11943), derived from interferometric observations with the L-band receivers of the MeerKAT radio telescope. I review the challenges in analysing the MeerKAT data and present...</p>

2023.04.25

Unveiling BCGs and their host clusters using the ICL and Satellite Galaxy Populations

<p>At the heart of every galaxy cluster is the brightest central galaxy (BCG). The central location of the BCG along with its unique formation history yield the underlying galaxy-dark matter halo connection. This statistical correlation allows us to enhance our understanding of the assembly and evolution of BCGs over cosmic time. However, we gain further insight into the formation and evolution of...</p>

2023.04.19

Galaxy-Scale Strong Gravitational Lensing at High Angular Resolution

<p>Anomalous flux ratios between lensed images can provide a key test of the dark matter sub-halo population, and hence the nature of dark matter. However, the observed anomalous flux ratios at radio frequencies can also be the result of systematics associated with our lack of knowledge about the source structure, source variability, propagation effects and microlensing of compact objects within t...</p>

2023.04.11

X-ray reflection spectroscopy on black hole X-ray binaries

<p>Black hole X-ray binaries are bright accreting systems that can undergo apparent state changes on the reasonable timescales for human. These systems are good analogy to their supermassive counterparts: active galactic nuclei. X-ray reflection spectroscopy is a powerful tool to study the accretion geometry under different regimes. In this talk, I will present how we use X-ray reflection spectros...</p>

2023.05.24

Toward Accurate Metallicity Measurements in ISM and Distribution of HI in CGM from 3D Spectroscopy

<p>Galaxies in the universe are intricately connected to the gas in and around galaxies. Accurately measuring the statistical properties of this gas is crucial for testing modern theories of galaxy formation and evolution. In this talk, I will present our recent efforts to characterize interstellar and circumgalactic media using integral field spectroscopy with high sensitivity in two aspects. 1) ...</p>

2023.04.21

Turbulence in outer protoplanetary disks

<p>Turbulence is essential to many fundamental processes in protoplanetary disks, including angular momentum transport, dust evolution, and planet migration. I will focus on two instabilities that can drive turbulent motions in outer disks. In the first part of this talk, a series of global 3D non-ideal MHD simulations via Athena++ code will be presented. The outer disk is found to be weakly MRI t...</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>

2022.05.25

Semi-analytic spectral fitting: simultaneously modelling the mass accumulation and chemical evolution in MaNGA spiral galaxies

<p>We develop a novel semi-analytic spectral fitting approach to quantify the star-formation histories (SFHs) and chemical enrichment histories (ChEHs) of individual galaxies. We construct simple yet general chemical evolution models that account for gas inflow and outflow processes as well as star formation, to investigate the evolution of merger-free star-forming systems. These models are fitted...</p>

2022.04.11

The Milky Way Halo Stars toward the Galactic Center

The halo stars on highly radial orbits should inevitably pass the center regions of the Milky Way, although they are hard to be detected from the crowded bulge/bar. Under the assumption that the stell...