Bachelor thesis with Prof. Mertsch in 2019

 

Stopping Cosmic Rays with Dark Matter

Context:
If dark matter interacts with ordinary matter, their annihilation or decay produces additional cosmic rays which can be searched for in data from experiments like AMS-02 on the International Space Station. Alternatively, ordinary cosmic rays from astrophysical sources can be affected by the exotic energy losses due to the presence of dark matter in the Milky Way. This would lead to markedly different spectra at the highest energies.

Goals:
After learning the basics of cosmic rays acceleration and transport, you will consider the exotic energy loss processes due to dark matter interactions. In particular, you will investigate the effect on the Boron-to-Carbon ratio, and derive constraints on the dark matter properties from observations.

Requirements:
An interest in the dark matter puzzle and some experience with solving differential equations.

Identifying nearby sources of cosmic rays

Context:
The observed spectrum of cosmic rays at Earth is a nearly featureless power law. However, small spectral variations are expected due to the presence of nearby astrophysical sources. A number of unexpected spectral features has been discovered in the last couple of years with a firm conclusion still elusive.

Goals:
In a Monte Carlo approach you will model an ensemble to galaxies similar to the Milky Way and consider the transport of cosmic rays from the sources to the observer. Quantifying the statistics of the particle spectra seen by an observer, you will be able to interpret the significance of some of the newfound features.

Requirements:
An interest to discover nearby sources of cosmic rays and willingness to learn some basic non-Gaussian statistics; previous programming experience would be great, but some code will be provided to get you started.

Solar modulation

Context:
Before being detected at Earth, charged cosmic rays propagate across the Solar System and undergo interactions with the turbulent solar wind and with the heliospheric magnetic field. These interactions have a major impact on the cosmic ray fluxes measured by detectors orbiting the Earth and therefore must be accurately implemented in any realistic cosmic ray propagation model.

Goals:
You will work on the development of a numerical code aimed at modeling cosmic ray transport in the heliosphere. You will then use such code to make theoretical predictions that will be compared to experimental data.

Requirements:
An interest in astroparticle physics, some experience with coding in C++.

Blazar flares from plasmoids

Context:
The most powerful sources of gamma-rays are blazars: jets from supermassive black holes pointing at the observer. The gamma-ray emission is likely produced in plasma bubbles, the so-called plasmoids, which are created by tapping the huge reservoir of energy stored in the magnetic fields. In such extreme environments, the interaction of high-energy particles and radiation fields must be considered self-consistently which leads to interesting non-linear phenomena.

Goals:
In this project, you will learn about the various interaction processes between matter and radiation in non-thermal sources and investigate how to solve the equations governing particle and gamma-ray spectra. You will build your own Monte Carlo code for modelling the time-dependent evolution of particle and radiation densities and statistically characterise the non-linear dynamics.

Requirements:
An interest in the most extreme radiation sources in the Universe and some experience with coding (Numerically solving sets of ODEs with python or Mathematica is enough.)