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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>

2022.12.22

Towards kHz Gravitational Wave Astronomy

<p>Gravitational wave has become a new window to explore our universe. Among many events detected so far, GW170817 was the first binary neutron star gravitational wave event joint with electromagnetic observations, which revolutionized our understanding of neutron star physics and the origin of kilonova. However, due to a limited detector sensitivity at the high frequency around kHz, we did not ob...</p>

2022.12.15

Solar coronal waves: A debate for two decades

<p>In 1997, the EIT telescope aboard the SOHO satellite (from NASA and ESA) discovered a global-scale wave phenomenon associated with solar flares, which was then called “EIT waves” or “solar tsunamis”. The physical nature of “EIT waves” has been debated for decades. The speaker will try to provide an overview of the related research, including recent progress.BIOPeng-Fei Chen is a solar phy...</p>

2022.12.01

Unveiling the astrophysics of cosmic reionization in the post-reionization era

<p>Cosmic reionization is the last major phase transition that our Universe goes through. In this milestone, the intergalactic medium transitions from primarily neutral, dark, and cold into mainly ionized, more luminous, and warmer. However, as exciting as the reionization process surely was, many aspects remain unknown, e.g. what are the sources of the ionizing photons? or what is the timeline of...</p>

2022.11.24

Multi-phase gas, accretion, and mechanical AGN feedback in early-type galaxies

<p>Most galaxies comparable to or larger than the mass of the Milky Way host hot, X-ray emitting atmospheres and central radio sources. Hot atmospheres and radio jets and lobes are the ingredients of radio-mechanical active galactic nucleus (AGN) feedback. About half of the most massive early type galaxies harbour multi-phase filamentary gas, which appears to result from the thermally unstable coo...</p>

2022.11.03

"brown dwarfs, are we stupid or you are just different?"

<p>Brown dwarfs are the latest discovered population on the HR diagram. They formed like stars but appearing like gaseous planets, thus bridging the gap between stars and planets. I will briefly introduce the research history of brown dwarfs and summarize the properties of known brown dwarfs. Then, I will explain the new discovered substellar transition zone formed by transitional brown dwarfs, an...</p>

2022.11.17

Cosmology with spectroscopic surveys

<p>Modern cosmology is an observational driven science. Two dark components, dark matter and dark energy, are introduced to explain the invisible mass inferred from various astrophysical observations and the accelerated expansion of the Universe. They represent around 95% of the total mass-energy budget of the Universe today. However, little is known about their nature.As a result of the competiti...</p>