GRAPPA MSc Thesis Projects

 

The following projects are Master Thesis Projects that have been defined by GRAPPA faculty members. Other thesis projects may also be available, please contact the relevant faculty members. See also GRAPPA members’ research interests. Please note that this is an evolving list, so come back in the future.

See the list of completed thesis projects.

Projects with a September 2018 start:

Diffuse supernova neutrino background

Core-collapse supernova explosions are one of the most spectacular events in astrophysics. They will produce copious amount of thermal (and possibly non-thermal) neutrinos, strong gravitational waves as well as electromagnetic waves. Although the occurrence rate is unfortunately small in the Milky Way, it is possible to detect the supernova neutrinos as diffuse background radiation. The purpose of this project is to provide the most realistic theoretical predictions of the flux of the diffuse supernova neutrino background and discuss the detectability at various detectors around the world. It would reveal the most violent aspect of the Universe.

Contact: Shin’ichiro Ando

Cosmic gamma-ray background from dark matter annihilation

If dark matter is made of weakly interacting massive particles, they may self-annihilate and imprint evidence in the cosmic gamma-ray background. The purpose of this project is to compute the flux and anisotropies of the gamma-ray background from dark matter annihilation, and especially to give precise assessment of uncertainties regarding model parameters for the large- and small-scale structure formation. These have to be understood very precisely and accurately, in order to obtain unbiased estimates of particle physics parameters of dark matter in the current and future observations.

Contact: Shin’ichiro Ando

Hunting for mysterious dark matter signature from 21 cm measurements

Recently EDGES found signature of 21 cm absorption line from neutral hydrogen between z = 15 and 20.  This signal can be interpreted as evidence of dark matter-baryon scattering.  In this project, you will be looking into various other constraints on this interpretation, and critically test if such an interpretation is really valid or can be further constrained with some future experiments. One can for example use neutrino data to constrain dark matter annihilating into neutrino pairs, a viable model proposed to explain the feature.

Contact: Shin’ichiro Ando

Probabilistic programming for astroparticle physics

Probabilistic programming is a rapidly developing field at the intersection between Machine Learning and Bayesian Statistics. One its promises is to enable the use of powerful ML techniques for principled and statistically rigorous statements about complex data. One of the more accessible implementations of probabilistic programming is provided by the python module `edward’, which builds on Google’s ML library TensorFlow. The student will familiarize him-/herself with the basics of probabilistic programming, ML and the concept of variational inference. The tool set will then be used to derive the most probable source class (e.g. blazars, pulsars, dark matter annihilation) for thousands of un-associated gamma-ray sources observed by the Fermi Large Area Telescope. If successful, the results of this project would provide insides into the particle nature of dark matter, and play a role in guiding future radio searches for pulsars.

Contact: Christoph Weniger

Sterile neutrinos in the early Universe and implications for dark matter

The arguably most plausible extension of the standard model of particle physics are right-handed “sterile” neutrinos. Via the see-saw mechanism, these particles could generate masses for the observed left-handed “active” neutrinos, they could play a role in the generation of the matter/anti-matter asymmetry in the Universe, and sterile neutrinos with masses in the few keV range provide a valid candidate for the dark matter in the Universe. Sterile neutrinos are produced in the very early Universe via their mixing with the active neutrinos. The production is described by density matrix equations that can be derived from the Kadanoff-Baym equations of non-equilibrium quantum field theory. The student will familiarize him-/herself with this formalism, and study implications for sterile neutrino dark matter in light of other observations using the global scanning tool GAMBIT.

Contact: Christoph Weniger

Searching for Dark Matter with the XENON1T detector

The XENON collaboration is operating the XENON1T detector, the world’s most sensitive direct detection dark matter experiment. The Amsterdam group is playing an important role in this experiment. The detector is operating at the Gran Sasso underground laboratory and consists of a so-called dual-phase xenon time-projection chamber filled with 3200kg of ultra-pure xenon. Our group has an opening for a motivated MSc student to do analysis with the data from this detector. The work will consist of understanding the signals that come out of the detector and applying machine learning tools to improve the reconstruction performance in our Python-based analysis tool. The final goal is to improve the signal-to-background for the dark matter search. There will also be opportunity to do data-taking shifts at the Gran Sasso underground laboratory in Italy.

Contact: Patrick Decowski

Various projects on accretion and jet production around compact objects

My group works on a variety of topics spanning astrophysics to astro-particle physics, mostly focused on accretion and subsequent jet production around compact objects, and their effect on the environment.   “Grappa-esque” projects could involve taking existing semi-analytical models and applying them to new multi-wavelength data sets, or even developing new models (or modules).   For more experimental types I would be interested in collaborating with KM3NeT folk on techniques to optimize transient searches (likely together with Shin’ichiro Ando and Aart Heijboer), or using CTA “data challenge” data to make predictions for CTA using our models.   Advanced programmers could have the option of working with our GRMHD simulations.   Please get in touch to discuss options if you are interested!

Contact: Sera Markoff

What impact do turbulent magnetic fields have on particle acceleration models?

For modeling spectral energy diagrams (SEDs) of supernova remnants one often uses simple models in which gamma-ray and radio and X-ray data are combined, using a single zone and a uniform magnetic field. Energetic electrons produce both gamma-ray emission through inverse Compton scattering and radio to X-ray emission through synchrotron radiation.  Multi-zones are already more advantages, but one aspect is always overlooked  for modeling X-ray synchrotron emission: the fact that it requires turbulent magnetic fields. This means that the constant magnetic field assumption is per definition wrong and that it may have led to biases in maximum energy estimates. For this project the idea is to investigate the impact the assumption of a turbulent magnetic field has on modeling basic particle accelerations models, namely what is the maximum electron energy inside the sources.

Contact: Jacco Vink

Modeling the ionization and heating in the interior of Cassiopeia A

My interests are not only confined to particle acceleration related to supernova remnants, and this project is only remotely related to particle acceleration: We recently measured the internal radio absorption of the remnant Cassiopeia A with LOFAR (Arias et al. 2018, ArXiv:1801.04887). This internal absorption informs us of the unshocked (cold) gas inside the shell, which has not been shocked and inform us about the evolutionary state of the remnant. However, to translate absorption into unshocked mass we need to know the temperature. Based on infrared data the temperature is assumed to be 200 Kelvin, suggesting a large mass of 2 Msun. However, it is not clear how the inside can be this hot, as radiation from the bright shell makes 30 Kelvin more likely. So for this project we would like to model the ionisation and heating in the interior of Cas A. It is likely that the state of the gas is not in equilibrium. So we would like to make time dependent modeling, using simple hydrodynamics and using heating from UV/X-ray emission from the hot shell. This is a challenging, but doable project that will require combining different modeling packages. My PhD student Maria Arias will co-supervise.

Contact: Jacco Vink

Particle acceleration efficiency of solar system shocks

With a past master student, I investigated the particle acceleration efficiency of solar system shocks. The idea was to test whether there was a critical Mach number (v/v_sound= M ~2.2) below which acceleration is suppressed. This project showed that for M > 2.2 the efficiency is not Mach number dependent and is about 5-10%. This project is a follow-up: look for shocks that are below 2.2 and find out whether they can accelerate and what the circumstances are under which they accelerate (since we found a few that indeed do not accelerate). In addition, we want to look at the magnetic field turbulence in the shock regions and connect it to the diffusion processes that are essential for the process of diffusive shock acceleration.

Contact: Jacco Vink

 


OLD PROJECTS:

Testing a generic primordial black hole population as a dark matter candidate by looking at radio and X-ray sky 

 The first direct detection of a gravitational wave signal, announced by the LIGO collaboration, demonstrated the existence of ∼30M black holes (BHs), prompting the suggestion that these objects are of primordial origin and may account for all of the Dark Matter in the Universe.

The presence of a population of primordial black holes in our Universe is heavily debated in these days in the scientific community, and in particular the possibility that these objects account for all the Dark Matter can be tested and constrained in many different ways, exploiting both cosmological and astronomical data.

If the Dark Matter is actually made of massive primordial black holes, there should be ~10^9 such objects in the Galactic bulge, and — given the large amount of gas in the inner part, close to the Galactic center — we expect them to accrete gas and show up as radio and X-ray sources in the sky 

We derived constraints on this hypothesis by comparing to the known X-ray and radio sources  in the Galactic center region (VLA and X-ray catalog), but those constraints are based on the assumption of a Dirac delta mass function.

The project consists in extending our results to arbitrary mass functions, in order to get a more robust and general constraint on the amount of primordial black holes in our Galaxy, in the 1 – 100 Msun mass range. The result may be an interesting and timely matter of debate in the astroparticle community and may result in a publication in a journal.

The student should have some experience in C/C++ coding: A package aimed at simulating the X-ray and radio emission from a population of PBHs is already present, and needs to be extended to generic mass functions. The student is expected to have some knowledge on the Dark Matter problem in general, and will acquire specific knowledge on the primodial black hole physics, and the physics of accretion of matter onto an isolated black hole.

Contact: Daniele Gaggero, Gianfranco Bertone

Probing Fundamental Physics with Gravitational Waves

The recent detection of gravitational waves by the LIGO collaboration was a landmark event.  It marks the dawn of a new era of gravitational wave astronomy and precision tests of gravity.  In this thesis, the student will explore what can be learned about the fundamental laws of physics from future gravitational wave observations. In other words, how does physics beyond standard model (of both particle physics and gravity) manifest itself in the gravitational wave signals?
The nature of the project will be exploratory, so the precise research direction will be developed in collaboration with the supervisor and is expected to evolve over time.  The thesis will require a strong background in theoretical physics, especially in quantum field theory and general relativity.

Contact: Daniel Baumann

Other Projects

Here is a list of MSc research projects that are available at Nikhef.