 
            <p>Despite the efforts made in recent decades to obtain more realistic stellar models, considerable uncertainties still remain due to our incomplete knowledge of some complex physical processes that occur within them, such as accretion, convection, mass loss, rotation, to name a few of them. Modeling these processes still relies on empirical calibrations and this has a significant impact on theore...</p>
<p>Photometric and spectroscopic observations of individual stars, binaries, and group of stars in coeval populations offer valuable insights into various stellar characteristics, such as chemical abundance, radial velocity, multiplicity, mass, distance, and age. The chemical abundances provide critical information about the internal physics of stars, the interactions between planets and their hos...</p>
<p>Cosmological formation of globular cluster</p>
<p>The dust content of protoplanetary disks plays a crucial role in the planet formation process. The key ingredients are not only the total budget of solid mass and the dust particle size distribution, but also how these are distributed throughout the protoplanetary disk. Characterizing the dust surface density, particle properties, and size distribution within the disk and its substructures is, ...</p>
<p>By analytically solving the Teukolsky gravitational wave equation for the spacetime of an ultracompact star of constant density, we derive exact and simple formulae that completely describe weakly damped oscillations trapped inside such stars. No similar complete analytic solution was known before, despite several attempts to find it. Our solution is cast in terms of the quasi normal modes of o...</p>
<p>In this talk, I will present the Adaptive Optics Facility (AOF) and the MUSE instrument at VLT/UT4.  AOF is the new generation cutting-edge adaptive optics system for the instruments at UT4.  With the high-performance deformable secondary mirror and 4 laser guide stars system, AOF enables to correct atmospheric turbulence effects on the optical wavelength, facilitating the Multi-Unit Spectrosco...</p>
<p>In this project, we aim to understand structures in galaxies from a deconstructive perspective. In a series of papers, we have developed an accurate, efficient, and unsupervised way that extracts structures of simulated galaxies in kinematics. We successfully identify kinematically-derived bulge, disk, and halo structures that have clear physical formation mechanisms in the IllustrisTNG simulat...</p>
<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>
<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>
<p>The precision measurements from current observational cosmology have established the Lambda-Cold-Dark-Matter (LCDM) model as the standard cosmological model. However, the LCDM model as a pure phenomenological model with six base parameters still calls for a theoretical understanding of underlying mechanisms for the early and late accelerations as well as the nature of dark matter. In this talk,...</p>