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2023.06.28
Kamioka CryoLab: A Future Low-background Underground Facility for Cryogenic Light Dark Matter Searches
<p>Dark matter — established via various cosmological and astronomical observations — is a significant constituent of our Universe and remains one of the most outstanding mysteries of modern physics. The mass range of potential dark matter candidates covers more than 30 orders of magnitude. In the past, researchers have primarily focused on searching for GeV-TeV dark matter (WIMP) via nuclear re...</p>
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2023.06.12
Cold molecular gas (cloud) properties across different types of galaxies
<p>As fuel feeding supermassive black hole and star formation, cold molecular gas is the key to many fundamental processes in galaxy evolution. In the last decade and especially with the advent of Atacama Large Millimeter/submillimeter Array (ALMA), it has become feasible to spatially resolve giant molecular clouds (GMCs) in a large number and a wide variety of galaxies. Here, I summarise my work ...</p>
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2023.06.28
Breaking bad degeneracies with Love relations: Improving gravitational-wave measurements through universal relations
<p>The distance-inclination degeneracy limits gravitational-wave parameter estimation of compact binary mergers. Such a degeneracy can be partially broken by including higher-order modes or precession when modeling the waveform of a binary that contains a black hole. But what about binary neutron stars, for which these effects are suppressed? In this talk, I will introduce a new parameterization o...</p>
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2023.06.13
Modeling realistic HII regions: Constraints from multidimensional nebular diagnostics
<p>As an important tracer of star formations and chemical enrichment in galaxies, HII regions play a fundamental role in our understanding of galaxy evolution. To infer the physical conditions of HII regions in galaxies, many diagnostic methods based on the emission-line spectra of the ionized gas have been proposed. Meanwhile, people have constructed theoretical models to describe the ionization ...</p>
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2023.06.05
The DESI Damped Lyα System Survey: Data Release 1
<p>We present the results of a Damped Lyman α (DLA) system survey in the Dark Energy Spectroscopic Instrument (DESI) Survey Data release 1. The concordance DLA catalog combines the prediction from two fully automated techniques: the convolutional neural network (CNN) model and the Gaussian Process (GP) model. For each absorber, we obtain an accurate measurement of the redshift, the HI column dens...</p>
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2023.06.09
Radiation MagnetoHydrodynamic Simulations of Astrophysical Systems: from massive stars to black holes
<p>Evolutions of stars, black hole accretion as well as interactions between stars and black holes play an important role in various astrophysical systems, such as supernova, X-ray binaries, AGNs as well as various transient phenomena. I will discuss some long standing issues related to massive star and black hole systems. Then I will describe some examples on how we can make progress on some of ...</p>
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2023.05.29
Galaxy/Quasar-Dark-Matter-Halo Connection of DESI: A Generalized Subhalo Abundance Matching Approach for Multiple Tracers
<p>LCDM is the standard model of modern cosmology with two dark components, dark matter and dark energy. The nature of dark energy and the dark matter structure growth rate can be probed via the large-scale structure (LSS). For this purpose, we observe millions of spectra of galaxies and quasars (QSOs) with spectroscopic galaxy surveys to explore the 3D map of the Universe. Meanwhile, high-resolut...</p>
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2023.06.12
The Power of Milky Way's Stellar Streams Enabled by Multi-Object Spectroscopic Surveys
<p>In this talk, I will discuss two ongoing spectroscopic programs to study the stellar streams in our Milky Way and highlight a few latest scientific results from these two programs. The Southern Stellar Stream Spectroscopic Survey (S5), started in 2018, is the first systematic program pursuing a complete census of known streams in the Southern Hemisphere. The science results from S5 include a ho...</p>
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2023.05.10
A dynamical model and structure decomposition of barred galaxies
<p>Galaxy structures are fossil records of their assembly history. Modern IFU spectrographs offer the ability to map the spatial distribution of the motions, ages, and chemical abundances of stars in galaxies, which provide unprecedented detailed view of galaxies structures. But the information are still blended along the line-of-sight. Decomposition of galactic structures in a physical way is cha...</p>
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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>
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