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2024.01.05

The circumnuclear gas in M81: a unique testbed for AGN and stellar photoionization

<p>The origin of the low-ionization nuclear emission-line region (LINER) prevalent in local galaxies and its relationship with supermassive black holes are debated for decades. We preform a comprehensive evaluation of traditional photoionization models against the circumnuclear ionized gas in M81, for which recent CAHA/PPAK integral-field spectroscopic observations reveal a LINER characteristic ou...</p>

2024.01.02

Expanding our perspective to the distant universe through Intensity Mapping of HI and CII

<p>As a prevalent and widely distributed component of galactic gas, neutral atomic hydrogen (HI) and Carbon lines (CO, CII) play a crucial role in comprehending various astrophysical processes, including star formation histories, galaxy interactions, and the tracing of cosmic large-scale structures. However, the sensitivity limitations of telescopes pose challenges to directly measuring line signa...</p>

2024.01.09

Deciphering Galaxy Quenching: Insights from the Multiphase Circumgalactic Medium

<p>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...</p>

2024.01.11

Witnessing the Birth of Planets: The Structure and Chemistry of Planet-Forming Disks

<p>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...</p>

2023.12.29

The lively radio transient sky

<p>Making use of exponential increases in computing power, radio astronomers have been able to search larger areas of the sky at high time and frequency resolution. These surveys facilitate the studies of radio transients, particularly contributing to the thriving investigation of fast radio bursts (FRBs), enigmatic radio bursts observable at cosmological distances. I will provide an overview of t...</p>

2023.12.29

Solutions towards the Hubble tension and S8 tension

<p>The standard LCDM model seems to fail to reconcile the discrepancy of the H0 measurements between the early and late Universe. This H0 tension has become an increasingly mystery in the cosmology community. Moreover, the galaxy survey measurement of S8 value, namely the amplitude of matter density fluctuation, is smaller than the value inferred from CMB assuming LCDM, although with a less signif...</p>

2023.12.25

Constraining the Cosmic Partition of IGM and CGM Baryons with FRB Foreground Mapping

<p>The frequency shifts measured in extragalactic Fast radio bursts (FRB)s probe the total column of ionized gas in the foreground, including large contributions from the CGM and IGM. By combining this information with both deep and wide &nbsp;spectroscopic observations of foreground galaxies, the information content is enhanced. The wide-field data &nbsp;(∼10s of Mpc scales) allows us to reconstruct the u...</p>

2023.12.22

The three regimes of atmospheric evaporation for super-Earths and sub-Neptunes

<p>A significant fraction of super-Earths and sub-Neptunes are thought to experience an extreme loss of volatiles because of atmospheric evaporation in the early stages of their life. Though the mechanisms behind the extreme mass loss are not fully understood, two contenders have been widely discussed: photoevaporation from X-ray and ultraviolet irradiation and core powered mass loss. In this talk...</p>

2023.12.25

A cooling anomaly of white dwarfs

<p>Data from the Gaia satellite are revolutionizing many fields of astronomy. I will present two related discoveries about white dwarfs: one is an extreme cooling anomaly upon phase transition of some white dwarfs, which stops their cooling for almost 10 Gyrs, and the other is the existence of merger products among single white dwarfs. I will show interesting solution to explain the anomaly and th...</p>

2023.12.19

A New AGN Photoionization Model and Multi-wavelength Metallicity Diagnostics

<p>The photoionization model of narrow-line regions (NLRs) in active galactic nuclei (AGNs) has been investigated for decades. Many published models are restricted to simple linear scaling abundance relations, dust-free assumption, uniform AGN radiation field, and using one specific photoionization code, which restricts them from providing a satisfactory prediction on a broad range of AGN observa...</p>