首页

2024.03.07

Galaxy-halo connection and near-field cosmology with numerical and semi-analytic methods

<p>In our modern understanding of the Universe, dark matter (DM) constitutes ~85% of the total mass and forms gravitationally bound halos which are the sites for galaxy formation. Galaxies contain information of their host halos, and halos react to the baryonic processes of the inhabitant galaxies — their connections are essential for understanding galaxy formation, and enable us to derive fundam...</p>

2024.01.12

Ultra-compact dwarf galaxies caught in the act of transformation

<p>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...</p>

2024.01.09

Exploring the new high-redshift frontier with the James Webb Space Telescope

<p>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...</p>

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>