Research
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2023.06.16
Flow Annealed Kalman Filters: Gradient-free inference for expensive forward models
For many scientific applications the forward model consists of an expensive black-box simulator without easy access to gradients of the forward model. In such a situation, inference can be challenging, with standard gradient-free sampling algorithms requiring an intractably large number of serial model evaluations. In this talk I will introduce the flow annealed Kalman filter for approximate Ba...
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2023.06.13
Modeling realistic HII regions: Constraints from multidimensional nebular diagnostics
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 ...
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2023.06.12
Cold molecular gas (cloud) properties across different types of galaxies
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 ...
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2023.06.12
The Power of Milky Way's Stellar Streams Enabled by Multi-Object Spectroscopic Surveys
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...
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2023.06.09
3D Structure and Extinction of Nearby Molecular Clouds
The 3D structure and extinction law are studied for the Taurus, Orion, Perseus and California molecular clouds (MCs) based on the LAMOST and APOGEE spectroscopy. Extinctions are calculated from color excess derived from the Blue Edge methods. In combination with the distance from the Gaia, a 3D extinction map and the structure of these MCs can be retrieved and the clouds that overlap in the sk...
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