<p>Turbulence is essential to many fundamental processes in protoplanetary disks, including angular momentum transport, dust evolution, and planet migration. I will focus on two instabilities that can drive turbulent motions in outer disks. In the first part of this talk, a series of global 3D non-ideal MHD simulations via Athena++ code will be presented. The outer disk is found to be weakly MRI t...</p>
<p>Understanding the physics of the interstellar medium is critical for understanding star formation and AGN feedback. Line ratio diagnostics diagrams, such as BPT diagrams, have been extensively used to study the ISM. However, their limitations hide inaccuracies of photoionization models, leading to a number of discrepant results in the literature on metallicity, abundance pattern, and correlatio...</p>
<p>We develop a novel semi-analytic spectral fitting approach to quantify the star-formation histories (SFHs) and chemical enrichment histories (ChEHs) of individual galaxies. We construct simple yet general chemical evolution models that account for gas inflow and outflow processes as well as star formation, to investigate the evolution of merger-free star-forming systems. These models are fitted...</p>
The halo stars on highly radial orbits should inevitably pass the center regions of the Milky Way, although they are hard to be detected from the crowded bulge/bar. Under the assumption that the stell...
Astrometry opened the era of modern astronomy/physics and plays a crucial role in contemporary astronomy, including the measurement of the three-dimensional structure of the Milky Way, black hole dete...
Much of the lensing effects in astrophysics can be adequately described using geometric optics, where light from a point source can be split into multiple magnified images. In coherent sources, such ...
The theory of General Relativity has successfully passed a large number of observational tests. The theory has been extensively tested in the weak-field regime with experiments in the Solar System and...
A major uncertainty in the determination of the mass profile of the Milky Way using stellar kinematics is the poorly determined anisotropy parameter, beta = 1 - ( ( (sigma_theta)**2 + (sigma_phi)**2 )...
Wide-field radio-interferometer surveys at high resolution, relatively low frequency and with very high dynamic range requirement play a prominent role in current and forthcoming radio astronomy progr...
Brown dwarfs and relatively isolated young extrasolar giant planets occupy an important parameter space to understand planetary atmospheres. Recent observations of these worlds have provided unprecede...