NCTS-TCA Summer Student Program 2023
理論計算天文暑期學校

The explosion engine and multi-messenger siganals from core-collapse supernovae are still elusive. In this project, the student will learn how to run multi-dimensional simulations of core-collapse supernova with magetic fields and neutrino transport. The student will also learn how to use Python to analysize and visualize simulation data. This project aims to find correlation bewteen magentic fields and neutrino/gravitational wave emissions.

Pre-requisites: Basic programming experience with Python
Keywords: magneto-hydrodynamics, raditaion transport, core-collapse supernova
Location: NTHU

The interstellar medium has very large physical extent and thus long dynamic timescales. Therefore, 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 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. The spherical collapse solution has already been derived. In this project, the student will work on cylindrical or planar geometry, which is more relavent to large-scale structure formation.

Pre-requisites: Calculus, Basic programming, Fluid mechanics
Keywords: Molecular cloud, Self-gravitating collapse, Radiative cooling
Location: NTNU

The non-ideal magnetohydrodynamic effects (ohmic dissipation, Hall effect, ion-neutral friction) play an important role in regulating disk formation. It has already been demonstrated that the protoplanetary disk, when still deeply embedded in the collapsing envelope, reaches an equilibrium radius as a result of self-regulation. Such models consider the vertical field lines that thread the disk, while the toroidal field is generated through induction. In this project, the student will look for the equilibrium solution when the disk is threaded by a horizontal field, and study whether the disk can reach a steady size during the mass growth.

Pre-requisites: Calculus, Basic programming, Fluid mechanics
Keywords: Protoplanetary disk, nonideal MHD
Location: NTNU

The First Hydrostatic Core (FHC) is a critical stage in the formation of a protostar, occurring after the initial collapse of a prestellar core. However, observing FHCs is challenging due to their small size, embedded nature, and short lifespan. This work utilizes radiative transfer tools to investigate the physical properties of FHC candidates, including density and temperature profiles, in order to gain insight into the earliest stage of star formation.

Pre-requisites: English reading ability
Keywords: star formation, radiative transfer
Location: NTHU

Jupiter is the largest planet in the solar system with its Galileo moons – Io, Europa, Ganymede and Callisto. The Galileo moons have fascinating phenomena. For example, Io is one volcanically active moon playing an essential role in shaping the magnetospheric environment of Jupiter. In addition, Europa is suggested to have putative outgassing plume activities which could be associated with its subsurface ocean. We will study the chemical composition and distribution of the atmospheres and plumes of these small bodies using with the numerical modelings (i.e., radiative transfer, exospheric model). This project will provide crucial information of the outgassing events of these small bodies by investigating the sources of the atmospheric species and their contribution to Jupiter’s magnetosphere. Our work will also provide complementary efforts to upcoming space missions, such as NASA’s Europa Clipper and ESA’s JUICE (both to be launched in 1-2 years).

Pre-requisites: Fortran and/or Python
Keywords: Galileo moons, Outgassing plumes, Magnetospheric plasma
Location: NTNU

Recent observations of very massive black holes already in place when the Universe was very young raise questions about how they can grow in such a short timespan. So far, there is no consensus on the growth model of these black holes. We aim to develop a numerical scheme to solve the differential equation governing the evolution of the black hole mass distribution function, with the purpose to test different growth models against the available observations.

Pre-requisites: Python programming
Keywords: Black holes, numerical methods
Location: NTNU, remote

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 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: intergalactic magnetic fields, ultra-high-energy charged particles, polarised synchrotron radiation, non-thermal processes, violent galactic starbursts
Location: NTHU, remote

Relativistic jets from supermassive black holes (so-called active galactic nuclei or AGN) at the center of galaxy clusters are believed to be the most promising feedback mechanism for heating the gas within galaxy clusters. However, the composition of the AGN jets is highly uncertain. In this project, we will learn how to perform hydrodynamic simulations with varied jet parameters to investigate their impact on the AGN feedback processes. We will analyze the simulation results using a Python-based software and compare the simulation predictions with observations.

Pre-requisites: General Astronomy; Basic programming (e.g. basic knowledge on Fortran, C, or Python is preferred but not required)
Keywords: hydrodynamics, galaxy clusters
Location: NTHU

When a star has consumed most of its nuclear fuel, it eventually comes to a point in its evolution in which the outward radiation pressure due to nuclear fusions can no longer support the gravitational pull. If the collapsing stellar core has a mass exceeding (approximately) three solar masses, degenerate pressure of neutrons can no longer support its gravitational collapse, leaving a black hole (BH) as an end product of stellar evolution. In addition to these stellar-mass BHs, there are much heavier BHs in the center of galaxies and globular clusters. For example, the Milky Way galaxy has a supermassive BH whose mass attains 4 million solar masses.
In this project, the student will learn the basic skills of black hole research, specifically general relativity and plasma physics, as well as numerical simulations. Depending on the academic and technical backgrounds of the student, she/he can get to touch on one or more of the following : how electron-positron pair plasmas are created, accelerated, and radiate emissions in BH magnetospheres; compare simulations with the blackhole multiwavelength observations; plasma physics around neutron stars; pulsar physics; learn to build visualization tools for simulations.

Pre-requisites: Solid college-level physics and mathematics, basic programming skills, and knowledge Special relativity. Basic skills in computer programing and/or visualization packages
Keywords: Computational Astrophysics, General Relativity, Black Hole, Plasma Physics, and CompAS
Location: NTU, remote

The variety of machine learning tools at our disposal make it timely that we apply them for cosmological data analysis. In this way, we may not only see whether these new tricks can give new cosmology insight, but also be able to test the robustness of the traditional Bayesian analysis. Our goal in this project is to study and use genetic algorithms -- a representative machine learning -- together with low redshift cosmological data (Pantheon+ and cosmic chronometers) to look at possible departures from the standard cosmological model by reconstructing the late-time redshift profile of the dark energy equation of state. If allowed by time constraints, we shall also study and apply neural nets for the same purpose.

Pre-requisites: Calculus, Python, Cosmology
Keywords: Hubble data, cosmological model inferencing, machine learning, genetic algorithm, Bayesian analysis
Location: Institute of Physics, Academia Sinica

Energetic feedback from active galactic nuclei (AGN) is a crucial process for understanding the formation and evolution of galaxies. It is believed that AGN feedback operates in two modes -- radiation-driven winds, or kinetic jets. Both feedback mechanisms could generate outflows from galaxy centers, forming structures like the Fermi bubbles in the Milky Way. However, their differences in the outflow properties and impacts on the galaxy are not fully understood. In this project, we will perform numerical simulations of AGN winds and jets in a disk galaxy, and compare the properties of the galaxies in order to understand their different impacts.

Pre-requisites: General Astronomy; Basic programming (e.g. basic knowledge on Fortran, C, or Python is preferred but not required)
Keywords: hydrodynamics, galaxies
Location: NTHU, remote

With advances in observational techniques and computing capabilities, we enter an era to investigate detailed mechanisms in high spatial and temporal resolution for processes responsible for the formation of protoplanetary systems like our own. In particular, we aim to study the active physical processes operating simultaneously with the ongoing formation and evolution of the powerful outflows in the earliest phases of the lifetimes of sun-like stars. We employ theoretical, computational, and observational methods for the convergence of key features.
We look for highly-motivated students who show a strong interest in learning numerical methods and tools, code development techniques, and their applications to star formation problems. The students will have hands-on experiences in various areas involved.

Pre-requisites: Good knowledge of Python, C/C++; college-level physics; English fluency; visualization software
Keywords: star formation; jets and winds; protostellar outflows; ALMA
Location: ASIAA, remote

Wave/Fuzzy dark matter (FDM) consists of ultralight bosons with mass ~1e-22 eV and features rich wave-like structures (movie). It is a promising alternative to standard cold dark matter (CDM) and could hold the key to solving some of the controversies surrounding CDM. Previous studies on FDM have mainly focused on low-mass isolated halos due to the huge computational costs of FDM simulations. In this project, we will address this important gap in the existing research and investigate, for the first time, the properties of FDM subhalos orbiting a Milky Way-sized host halo, including tidal stripping, dynamical friction, and their central solitons. Using the state-of-the-art FDM code GAMER-2, the student will gain hands-on experience in cutting-edge dark matter research and high-performance parallel computing.

Pre-requisites: General astronomy, basic knowledge of Python, C, and Linux
Keywords: Dark Matter, Galaxies, Numerical Simulations
Location: NTU, remote

The charged icy grains are subject to several forces, among which gravity and Lorentz force. As the grains travel in space, their mass and charge both vary due to sublimation and charging effects. We will study the consequences on the orbital trajectories of these grains in the rings of Saturn.

Pre-requisites:Calculus, Basic programming, Fluid mechanics
Keywords: Molecular cloud, Self-gravitating collapse, Radiative cooling
Location: NTNU, remote