| 1. On the Dynamical Evolution of Extra-Solar Planetary Systems |
| It is known that thousands of extra-solar planetary systems are detected by either ground-based telescopes or space telescopes. Among these, there are hot Jupiters, cold Jupiters, super-Earths, mini-Neptunes, and so on. Given the diversity of these systems, it is important to further understand the dynamical evolution of these planetary systems and thus address their formation processes. These theoretical results will be directly used to interpret the data from current or future space telescopes such as TESS, CHEOPS, and Twinkle. |
| Pre-requisites: none |
| Keywords: extra-solar planetary systems |
| Supervisor: Ing-Guey Jiang (NTHU) |
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| 2. Effects of Magnetic Field and Viscosity on Ram-pressure Stripping of Galaxies |
| When galaxies fall into a galaxy cluster, the high pressure of the intracluster medium (ICM) would blow away gas within the galaxy, forming a tail behind the galaxy. This process is called "ram-pressure stripping." Previous simulations have typically modelled this process using purely hydrodynamic simulations; however, magnetic fields and viscosity could have non-negligible influence on the results. In this project, we will learn how to perform numerical simulations of galaxy stripping in clusters, and compare the results from simulations with different assumptions about magnetic fields and viscosity using a Python-based software. |
| Pre-requisites: General Astronomy; Basic programming (e.g. basic knowledge on Fortran, C, or Python is preferred but
not required) |
| Keywords: hydrodynamics, magnetohydrodynamics, galaxies |
| Supervisor: Hsiang-Yi Karen Yang (NTHU) |
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| 3. Dynamical Buoyancy of Globular Clusters in Wave Dark Matter |
| Wave/Fuzzy dark matter (FDM) has been a promising alternative to the standard cold dark matter (CDM) due to its potential of solving the small-scale controversies of CDM while retaining the same large-scale structure. The model consists of ultralight bosons with mass ~10^{-22} eV and features rich wave-like structures, including a central solitonic core surrounded by an extended granular halo. In this project, we will conduct numerical simulations using the state-of-the-art FDM code GAMER-2 to investigate how the solitonic core may reduce the dynamical friction and explain the large orbital radii of globular clusters in dwarf galaxies. |
| Pre-requisites: Calculus; Basic knowledge of C and Python |
| Keywords: Dark Matter, Galaxies, Numerical Simulations |
| Supervisor: Hsi-Yu Schive (NTU) |
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| 4. Heating of Stellar Streams by Wave Dark Matter Fluctuations |
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Wave/Fuzzy dark matter (FDM) has been a promising alternative to the standard cold dark matter (CDM) due to its potential of solving the small-scale controversies of CDM while retaining the same large-scale structure. The model consists of ultralight bosons with mass ~10^{-22} eV and features rich wave-like structures, including a central solitonic core surrounded by an extended granular halo. In this project, we will conduct numerical simulations using the state-of-the-art FDM code GAMER-2 to investigate how the fluctuating density granules may disturb and thicken the cold and thin stellar streams in our Milky Way, which will help constrain the FDM particle mass. |
| Pre-requisites: Calculus; Basic knowledge of C and Python |
| Keywords: Dark Matter, Galaxies, Numerical Simulations |
| Supervisor: Hsi-Yu Schive (NTU) |
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| 5. Semi-analytical Models of Forming Planet-forming Disks |
| Recent observations show that there are many planets around other stars. Their sizes and structures are so diverse that they are set in the initial stages of planet formation. In this project, the student will work with differential equations that describe the collapse of a dense core. A dense core is a gravitationally bound object that can collapse to form a star and a disk. These solutions are then coupled to a radiative transfer code to calculate the temperature structure. The project will be composed of solving differential equations, basic programming, and executing the radiative transfer code on a high-performance computing platform. |
| Pre-requisites: Calculus, Python (C++ or fortran will help) |
| Keywords: star formation, planet formation, collapse of dense cores,
radiative transfer |
| Supervisor: Daniel Harsono (NTHU) |
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| 6. Properties of Orbiting Hotspots in the Vicinity of Black Holes |
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Exciting international efforts, such as GRAVITY and Event Horizon Telescope collaborations, have made horizon-scaled observations possible. The dynamical electromagnetic signals from the vicinity of black holes provide unique opportunities for testing general relativity and exploring properties of the black hole system. In the project, by applying a general relativistic ray-tracing code -- Odyssey, we aim to model orbiting hot spots around black holes, and study the dynamical, observable features of the spots. |
| Pre-requisites: general relativity, C and Python programming |
| Keywords: black hole, general relativity, numerical method |
| Supervisor: Hung-Yi Pu (NTNU) |
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| 7. Modeling Emission from Astrophysical Flows around Galaxies |
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Flows of matter in and out of galaxies form an important component of cosmic “recycling” processes that affect how galaxies evolve. Multi-phase flows of hot, tenuous gases, cold dense clumps and relativistic particles can pass between the circum-galactic environment and the interstellar medium of a galaxy, regulating activities such as star-formation. In this project, we will model observational signatures of the physical structure and composition of these flows. This will be important to understand more clearly how they impact on an evolving galaxy and its internal environment. |
| Pre-requisites: General astronomy and physics, including fluid mechanics, basic programming (e.g. Python/Fortran). |
| Keywords: Theoretical astrophysics, galaxy evolution, circum-galactic medium |
| Supervisor: Ellis Owen (NTHU) |
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| 8. Investigating the High-energy Emission from Violent, Star-forming Galaxies |
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Star-forming galaxies are violent astrophysical environments, and can operate as factories of energetic particles called cosmic rays. These cosmic rays can interact within star-forming galaxies to produce high-energy radiation, which we can use to investigate their role in galaxy evolution. In this project, we will investigate high energy cosmic ray processes in star-forming galaxies, and learn how internal galaxy conditions can modify their high-energy emission signatures. |
| Pre-requisites: General physics. Basic programming (e.g. Python/Fortran) is preferred but not essential. Basic astronomy helpful, but not required. |
| Keywords: Theoretical astrophysics, cosmic rays, gamma-rays, high energy astrophysics, star-forming galaxies, galaxy evolution |
| Supervisor: Ellis Owen (NTHU) |
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| 9. Polarised Synchrotron Radiation from Ultra-high-energy Particles in Non-thermal Magnetised Intergalactic Media |
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Galaxies in close proximity interact continuously, thus exhibiting episodes of collective violent starbursts and quenching. These activities were frequent among proto-galaxies, when the Universe was young and dense. Due to the extreme interactions, ultra-high-energy particles and turbulent magnetic fields were often expelled into the intergalactic space. This study aims to determine the polarised synchrotron radiation from complex, non-thermal magneto-ionic plasmas around groups of proto-galaxies. Under guidance, the student will learn to build scenarios, construct models and carry out numerical computations on the high-performance computing clusters, mainly using the cosmological polarised radiative transfer (CPRT) code developed in-house by the supervisors. |
| Pre-requisites: Preferably a 2nd-year student, who is interested in high-energy astrophysics in the early Universe. Familiar with Python. Willing to learn Fortran. |
| Keywords: polarised synchrotron radiation, non-thermal processes, ultra-high-energy charged particles, violent galactic starbursts, intergalactic magnetised media |
| Supervisor: Alvina Y. L. On (NTHU/NCTS) & Jennifer Y. H. Chan (U Toronto) |
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| 10. Rarefied Gas Dynamics of Mass Transport Process on Saturnian Rings |
| Saturn's diffuse E ring extends from 3 to 8 Saturnian radii (Rs) with a peak of brightness near the orbit of the icy satellite Enceladus (3.95 Rs). It was suggested that the water plume on Enceladus can be the source of the E ring and it also can be a supply of water ice on Saturn's main ring (1.2 - 2.3 Rs). In this project, we will learn the numerical simulations of rarefied gas dynamics of mass transport from the water vapor plume of Enceladus to Saturn's main ring and its atmosphere including the photochemical process and three-body gravitational effect. |
| Pre-requisites: Basic knowledge of C |
| Keywords: Enceladus, Saturn Ring, Numerical Simulations |
| Supervisor: Ian-Lin Lai (NTNU) |
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| 11. Noncanonical Methods for Cosmological Parameter Estimation |
| Cosmological parameters tell us about the Universe's expansion rate as well as the growth of matter within. These are traditionally inferred by means of Bayesian analysis together with a set of cosmological observations and a model. On the other hand, there is an abundance of alternative statistical methods that may complement this canonical viewpoint of cosmological analysis by providing independent estimates of the physical parameters. We study and apply a selection of these methods (e.g., approximate Bayesian computation, genetic algorithms, neural networks) on real cosmological data and so add insight into the robustness of the values of the cosmological parameters obtained traditionally. We assess the perks and quirks of each method related to their impact on the analysis of the standard cosmological model and, if allowed by time constraints, beyond. |
| Pre-requisites: Calculus, Python, Cosmology. |
| Keywords: Hubble constant, growth rate, Bayesian statistics, reconstruction method, data analysis, machine learning |
| Supervisor: Reginald Christian Bernardo (ASIoP) |
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| 12. Chaos in Interstellar Shocks |
| Stars form in the cold and dense cores of molecular clouds. Many observations and numerical simulations suggest that molecular clouds exhibit supersonic and magnetized turbulence. The resulting shocks can have critical impacts on the environment of star-forming clouds, where the ions and magnetic fields drift away from the neutrals (a.k.a. ambipolar diffusion). Of particular interest in this project is the interplay between ambipolar diffusion and shocks. Our team performed both the local instability analysis as well as numerical simulations and found that these shocks are dynamically unstable and can become chaotic. As a continuous effort of theoretical prediction, we are inviting a summer student to work with us to better understand the shock substructure. |
| Pre-requisites: Students majoring in physics, mathematics, or any related topics with basic knowledge of physics are all considered. Experience in Linux/Unix and programming is desirable but not required. |
| Keywords: shock, plasma astrophysics, molecular clouds, star-forming regions, interstellar magnetic fields |
| Supervisor: Pin-Gao Gu (ASIAA) |
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| 13. "Listening" to Black Hole Portrayal |
| The direct detection of gravitational waves emitted from binary black hole mergers ushers in a completely new era of gravitational wave astronomy. Interestingly, the properties of post-merger signals are strongly related to those of light rays propagating around the black hole, as well as those of the critical curve in the black hole image. In this project, we will discuss the theoretical foundation of post-merger ringings and the black hole image. Then, we will discuss how these two seemingly independent observables are actually related and how one can probe black hole spacetimes using these two observables. |
| Pre-requisites: Calculus, Basic level of General Relativity, Mathematica |
| Keywords: Black holes, gravitational waves, gravitational lensing |
| Supervisor: Che-Yu Chen (ASIoP) |
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| 14. Gas Outflow with Icy Dust Accelerated/Decelerated by Sublimation |
| We will apply the Parker Solar wind model to the outflow of cold gas from icy bodies. The main differences are 1) the outflow is powered by the Solar irradiation, 2) the outflow is a mixture of gas and icy dust grains, and 3) the proportions of gas and dust can evolve in the outflow due to further sublimation. We will adapt the model and find the solution for this new hydrodynamical system. This will tell whether the outflow is facilitated or suppressed by the ice sublimation, and in which conditions the icy dust can escape. We will also look for an effective equation of state for the moist gas. |
| Pre-requisites: Calculus, Basic programming, Fluid mechanics |
| Keywords: Radiative heating and cooling, icy dust sublimation, hydrodynamics |
| Supervisor: Yueh-Ning Lee (NTNU) |
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| 15. Radiative Cooling of Molecular Gas under Self-gravitating Collapse |
| The interstellar medium is so diffuse that, when compressed during the collapse, the increased internal energy can be lost through radiation. In consequence, the gas heats up less efficiently than what would have been expected for a gas under adiabatic compression. We will solve the Navier-Stokes equations to find a self-similar spherical collapse solution. With this, an effective equation of state of the gas can be obtained, with which we no longer need explicit expression of the radiative cooling. |
| Pre-requisites: Calculus, Basic programming, Fluid mechanics |
| Keywords: Molecular cloud, Self-gravitating collapse, Radiative cooling |
| Supervisor: Yueh-Ning Lee (NTNU) |
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| 16. Multi-wavelength Signatures of Cosmic Rays in Dense Molecular Clouds |
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Energetic charged particles called cosmic rays propagate through and interact with the multiphase interstellar medium. Their engagement with the dense molecular cloud component of the interstellar medium of a galaxy can be traced by multi-wavelength radiation signatures, and these can be used to reveal crucial new information about the physical conditions inside clouds. In this project, we will investigate these signatures and learn about how they can be used to probe the density structure and magnetic field of molecular clouds. |
| Pre-requisites: General physics. Basic programming (e.g. Python/Fortran) is preferred but not essential. Basic astronomy helpful, but not required. |
| Keywords: Theoretical astrophysics, cosmic rays, gamma-rays, high energy astrophysics, star-forming galaxies, galaxy evolution |
| Supervisor: Ellis Owen (NTHU) |
