Title: Capturing moons from L4/L5

Supervisors: Tjarda Boekholt (t.c.n.boekholt@uva.nl) and Silvia Toonen (S.G.M.Toonen@uva.nl)

Project type:  Theoretical Astrophysics, Computational Astrophysics

Tidal capture is thought to be the origin of some observed Solar System moons with eccentric and inclined orbits.  Capture is more probable if the approach speed is low, such that a smaller amount of energy dissipation can already be sufficient for capture.  

A potential source of low velocity bodies can be the L4/L5 Lagrange regions of a planet. 

Bodies diffusing from these regions will subsequently experience low velocity close encounters with the planet, during which tidal dissipation might lead to the capture of the moon.   The student will use the tidal N-body code TIDYMESS and study the dynamics of this channel in detail.

 

Title:  Seize the powerlaw: robust statistical characterization of lightcurves from real and simulated accreting black holes

Supervisors:  Oliver Porth (O.J.G.Porth@uva.nl) and Phil Uttley

Project type: Computational Astrophysics, Observational Astrophysics, Applied Data Science

When matter gets swallowed by black holes, it does not go quietly: before vanishing forever, gas is heated to extreme temperatures which causes it to emit across the electromagnetic spectrum.  Furthermore, the orbital motion and the turbulent processes that govern the gas dynamics are thought to leave an imprint on the emitted light.  For example, a typical observed lightcurve (recorded photons as function of time) shows fluctuations on multiple timescales which can be related back to the physical processes near the black hole, and this is what we are after!  But to make this connection, we first need to firmly establish which features are in fact real and which ones are likely to vanish with more data.  In this project, you will take a new approach to lightcurve modeling and use advanced statistical models called "Gaussian process modeling", to analyze data obtained from general relativistic computer models and from real observations.  With this tool in hand, you will be able to say whether and where there are special frequencies in the data (e.g. breaks in a powerlaw) and whether we can use the properties of lightcurves to distinguish between different models of the accretion flow, e.g. can we distinguish lightcurves from weakly magnetized flows and strongly magnetized flows?  

This project allows you to make connections to state-of-the art computer models as well as statistical and observational data analysis.  

 

Title:  Towards the speed of light with the speed of GPUs

Supervisors:  Oliver Porth (O.J.G.Porth@uva.nl)

Project type: Computational Astrophysics

Modeling of relativistic gas- or plasma- dynamics is a core aspect of High-Energy astrophysical research.  The tool of choice is often general relativistic magnetohydrodynamic simulations which allow us to study the physical processes near compact objects with the computer.  Recently, the group has ported a big chunk of our community codes (AMRVAC/BHAC) to use modern graphics processor units (GPUs). The new fast code (AGILE, https://github.com/amrvac/AGILE-experimental ) can already do a lot of things (e.g. adaptive mesh refinement multi-GPU simulations of physics relevant for solar and interstellar medium environments), but the relativistic physics modules are not yet present.  In this project you will change that!  The goal is to port over the special relativistic hydrodynamic physics module which can be applied to study a host of high energy phenomena such as relativistic jets and gamma-ray bursts.  You will gain first hand experience with high-performance computing, performance optimization and the exciting physics of astrophysical relativistic flows.  If you enjoy numerical and computational methods, this project could be a great fit!  

 

Title:  GPU-accelerated magnetohydrodynamics

Supervisors: Dr. Philipp Mösta (p.moesta@uva.nl), Sara Azizi, Pravita Hallur

Project type: Computational Astrophysics

This project will involve porting and profiling individual computation kernels for our GPU-GRMHD code GRaM-X. GRaM-X is a dynamical-spacetime general-relativistic magnetohydrodynamics code for simulation binary neutron-star mergers and supernova explosions. The project is flexible and can be focused on performance testing and optimization of existing modules of the code for specific GPU architectures or developing new physics modules (e.g. neutrinos, equation of state, magnetic fields). The former will give the student experience working with state-of-the-art GPU systems and gain insights into modern GPU programming while the latter also involves algorithm development for computational physics in astrophysical magnetohydrodynamic simulations.

 

Title: How messy is a stellar crash?

Supervisors: Jakob van den Eijnden (a.j.vandeneijnden@uva.nl) and Julia Bodensteiner

Project type: Observational Astrophysics

Description: While massive stars (with initial masses > 8 times the mass of our Sun) are rare and short-lived, they play an outsized role in shaping the Milky Way: they create metals and distribute these across the Galaxy in supernovae, and launch powerful winds that shape their surroundings. An extreme example of how massive stars shape their close environment is seen in HD 148937: this massive star is surrounded by multiple dense shells of gas that have been expelled from the star in the past. Recent research has suggested that HD 148937 formed when two massive stars that orbited around each other, crashed and merged, causing ejections of the material that we now see around the star. 

A crucial question about this colossal stellar merger remains unanswered: how much mass was actually lost when the two stars merged? In this project, you will answer this question by combining data at two wavelengths: optical images, specifically Halpha, and radio images, specifically at 21 cm. You will model the emission processes in both observing bands to produce a map of the density of the ejected gas shells; then, you will design a geometrical model for the shells and estimate the total amount of mass lost when the stars merge. Your measurements will help us unravel this poorly understood merger process. 

(Because text does not do justice to the beauty of this object, you can see an image on the front page of https://www.eso.org/sci/publications/messenger/archive/no.194-mar25/messenger-no194.pdf)

 

Title: Do thermonuclear explosions make an accretion flow wobbly?

Supervisors: Chuanyu Wei, Jakob van den Eijnden (a.j.vandeneijnden@uva.nl) , Nathalie Degenaar

Project type:  Observational Astrophysics

When neutron stars live in a binary systems with a low-mass star, the neutron star’s gravity may capture and attract the outer layers of this companion star. This material gradually flows towards the neutron star in a disk, called an accretion disk, slowly loosing its angular momentum. Once it reaches the neutron star, the gas piles up on the surface, where extreme density and temperature conditions may lead to runaway nuclear fusion. The effect is a thermonuclear burst, an explosion that lasts a few seconds and reaches 100.000 times the luminosity of the Sun. With this extreme brightness, these explosions influence the flow of gas that caused them in the first place: we have recently found one binary system where the accretion flow shows long-lasting fluctuations in its brightness and temperature due to the extreme influence of the burst. 

In this project, you will help us investigate if this behaviour — this unstable, ‘wobbly’, accretion flow after a burst — occurs more commonly in other binaries as well. You will investigate archival X-ray observations from space missions such as the Rossi X-ray Timing Explorer and NICER; develop a technique to identify this accretion flow behaviour; and investigate if its occurrence depends on the other properties of the binary. Both potential outcomes, finding no other systems or finding many other systems that show this behaviour, will be of scientific value and help us understand the complex effect of bursts on accretion flows. 

 

Title: Sneak Peek Inside the Accretion Disk of X-ray Binaries with XRISM

Supervisors: Eleonora Caruso (e.caruso@uva.nl), Elisa Costantini (e.costantini@sron.nl), Nathalie Degenaar (N.D.Degenaar.uva.nl)  

Project type: Observational Astrophysics

X-ray binaries (XRBs) are interacting systems where a compact object—either a neutron star or a black hole—accretes material from a companion star, forming a rotating accretion disk. Close to the compact object, temperatures and energies become extreme, causing the disk to emit intense X-ray radiation. Studying this emission helps us understand how matter falls onto compact objects, how accretion disks are structured, and how matter behaves under extreme physical conditions.

In this project, you will analyze X-ray spectra from an X-ray binary system observed by the newly launched XRISM space mission, a collaboration between JAXA, NASA, and ESA. These observations provide the highest spectral resolution X-ray data ever obtained for these sources, giving you a unique opportunity to explore the extreme physics at play, and take a closer look straight inside the accretion disk of X-ray binaries.

 

Title: Tracing Interstellar Iron toward Cygnus X-1

Supervsiors:  Ioanna Psaradaki (Ioanna.Psaradaki@esa.int), Elisa Costantini, Nathalie Degenaar

Project type:  Observational Astrophysics

Iron is a key element in the Universe and an important tracer of the physical and chemical conditions of the interstellar medium (ISM). In this project, we investigate the distribution of iron in our Galaxy along the line of sight toward the bright X-ray binary Cygnus X-1, one of the most well-studied X-ray sources in the sky. We combine ultraviolet (UV) spectroscopic observations from the Hubble Space Telescope (HST) to measure iron in the gas phase with high-resolution X-ray spectroscopy from the Chandra and XMM-Newton observatories to probe iron locked into interstellar dust grains. By analyzing absorption features in both wavelength regimes, we aim to estimate the total iron abundance and determine how iron is partitioned between gas and dust in the ISM.

 

Title: Do helium stars lose mass more quickly in the Milky Way than in the Magellanic Clouds? 

Supervisors: Jakob van den Eijnden (a.j.vandeneijnden@uva.nl), Mitchel Stoop, Sarah Brands, Julia Bodensteiner

Project type: Observational Astrophysics

The majority of massive stars (with initial masses > 8 times the mass of our Sun) are born in binary systems. Some of these end their lives, after billions of years, as merging compact objects (black holes and/or neutron stars), detected via their gravitational wave emission. In between birth and merger, these binaries pass through many phases, some of which cause mass to be transferred from one star to the other. It is therefore expected that these binary pass through phases where only their ‘stripped’ helium cores remain. In order to understand how the system evolves after that stage, a key ingredient is the ‘mass-loss rate’ of these stripped helium stars: how quickly do they continue to lose material even after only their helium core remains? 

Currently, this mass-loss rate has only been measured for stripped helium stars in the Magellanic Clouds, where the metallicity of stars is lower than in the Milky Way. Mass-loss is expected to be stronger for more metal-rich stars; the goal of this project is to test if that is true by analysing new radio observations of the first Galactic example of a stripped helium star. You will work with data that will be observed with the Australia Telescope Compact Array in early 2026. From the calibrated observations, you will create images, investigate the emission of the binary, and model the mass-loss rate of a Galactic stripped helium star for the first time. 

 

Title: Decoding Disks: Statistical Analysis of Disk Variability in Classical Be Stars
Supervisors: Julia Bodensteiner (j.bodensteiner@uva.nl) & Daniela Huppenkothen (d.huppenkothen@uva.nl)

Project type: Observational Astrophysics, Applied Data Science

Massive stars are cosmic engines: they trigger star formation, drive the chemical evolution of galaxies, and are sources of gravitational waves. Despite the large impact on their environment, a subgroup of massive stars, the rapidly rotating classical Be stars, still pose many open questions. Classical Be stars are characterized by the presence of a circumstellar disk, formed from material ejected by the star itself and responsible for distinctive emission lines observed in their spectra. Understanding the variability of these disks is crucial for unraveling the mechanisms of disk formation, evolution, and dissipation-processes that remain only partially understood.

In this project, you will investigate the emission-line variability of a sample of ~200 classical Be stars using optical multi-epoch spectroscopy. In combination with statistical methods, you will quantify the variability, analyze relevant timescales, and identify potential patterns in the data. This will allow to draw conclusions about the physical processes causing the disks to form, which is crucial to improve our understanding of the Be phenomenon.

 

Title: Shining new light on black hole accretion states with disk variability

Supervisors:  Phil Uttley (P.Uttley@uva.nl), Matteo Lucchini
Project type:  Observational Astrophysics

Note: Can take up to 2 students to work on different aspects of this topic.

Accreting black holes in outbursting X-ray binary systems are seen to evolve through distinct 'accretion states' which correlate with the switch-on and switch-off of relativistic jets, as well as major changes in the nature of rapid variability seen in the X-ray light curves. The variability is probably produced by turbulence in the accretion disk, triggered by a magnetic field threading the disk. If the magnetic field evolves during an outburst, it could explain the changes in the variability, jet and X-ray spectrum in the different accretion states. 

In this project you will use data from NASA's NICER X-ray observatory to directly measure the accretion disk variability and combine your results with the latest models, to work out where the variability is produced in the disk and how that changes during an outburst, as the magnetic field also changes. Your results could shed new light on how the disk magnetic field evolves during an outburst, which is a key step towards solving the mystery of black hole accretion states.

This project will involve working with X-ray data from accreting black holes using Python software to analyse the variability and compare with physical models. While it does not involve programming the methods from scratch, some knowledge of Python scripting will be useful to set up the analysis.

 

Title: Exploring the black hole’s accretion disk with X-ray spectroscopy

Supervisors:  Elisa Costantini (E.Costantini@sron.nl), Phil Uttley

Project type:  Observational Astrophysics

Active galaxies (AGN) host a supermassive black hole, whose accretion and ejection activity is not yet fully understood. The AGN most evident spectroscopic signature of accretion is emission from iron. These emission lines may be distorted by relativistic effects.  In this project the student will study a high-resolution X-ray spectrum of a bright AGN using the data of the JAXA satellite XRISM. This AGN  is known to host a multicomponent emission system. In this project the student will learn about AGN and their importance in the universe and will get familiar with high-resolution spectroscopy.

 

Title:  Testing the dense matter equation of state using neutron stars

Supervisors: Anna Watts (A.L.Watts@uva.nl) , Nathan Rutherford

Project type:  Theoretical Astrophysics

Note: Can take up to 2 students to work on different aspects of this topic.

Neutron stars contain matter at several times nuclear density: under such conditions it can reach unprecedented levels of neutron-richness, and stable states of strange matter may form.  Neutron stars may even contain some dark matter! Using properties such as neutron star mass and radius, which depend on the state of matter in the neutron star core (what we call the equation of state), we are able to place constraints on nuclear physics.  Over the last few years we have developed a Python-based equation of state inference code, NEoST, that takes mass-radius measurements (derived from X-ray observations) and mass-tidal deformability measurements (derived from gravitational wave observations) and uses them to place constraints on state-of-the-art dense matter models from our nuclear physics collaborators.

Over the next few years we expect to see the first precision measurements of neutron star moment of inertia, another quantity that depends on the equation of state.   And as our mass-radius measurements get better, we will also need to improve our treatment of neutron star rotation (currently neglected in our equation of state calculations).  You will work on one of these two aspects, developing new modules for NEoST to capture this physics, and testing them using a mix of real and simulated data.

 

Title: Let the planet hunt begin! Searching for an exoplanet around a radio-bright star

Supervisors: Elise Koo (e.j.m.koo@uva.nl) and Joe Callingham (callingham@astron.nl)

Project type: Observational Astrophysics

In this project, you will analyse radial velocity data to investigate whether the nearby star GJ 450 hosts an exoplanet. GJ 450 is known to be radio-bright, and its radio emission may be produced by magnetic interactions between the star and an orbiting planet. Detecting a planet around GJ 450 could therefore provide valuable evidence for magnetic star-planet interactions, which offer a novel way to probe exoplanet magnetic fields. This project offers experience with state-of-the-art radial velocity data and modern techniques used in exoplanet discovery. It is well-suited for students with basic programming skills in Python and an interest in exoplanets and observational astronomy. You will also have the opportunity to visit ASTRON, the Netherlands Institute for Radio Astronomy, if that interests you.

 

Title:  Are dust aggregates aligned when settling in gas?

Supervisors:  Niels Swinkels and Carsten Dominik (c.dominik@uva.nl)

Project type:  Theoretical Astrophysics, Computational Astrophysics

Write a direct molecular dynamics simulation (DSMC) of a fractal aggregate embedded a rarified gas, to study the behavior during planet formation. Dust aggregates are made from sub-micron particles stuck together by van der Waals forces to form an irregular, fractal structure. During planet formation, these are embedded in gas and move relative to the gas.  We want to study the rotational/alignment properties of these aggregates in a Bachelor project.  Required: Good programming skills, High level Python with good use of numpy, or better a compiled language.

 

Title:  Floating fractals

Supervisors:  Carsten Dominik (c.dominik@uva.nl)

Project type:  Theoretical Astrophysics

In planet-forming disks, sub-micrometer-sized particles collide and stick to form fluffy, fractal aggregates. Such aggregates are better couple to the gas than compact particles with the same mass. Depending on the exact growth process, even large aggregates may be lifted t the surface of the planet-forming disks where they can interact with light and be detected with our most-modern telescopes.  In this Bachelor project, we want to compute the largest aggregate that will still be visible, as a function of fractal dimension (= formation process) and the strength of turbulent mixing in the disk. Required: Good physical understanding in insight, programming skills.

 

Title:  Exoplanet Atmospheres: Clouds and Their Role in Planetary Chemical Evolution

Supervisors:  Antonija Oklopčić (a.oklopcic@uva.nl)

Project type:  Theoretical Astrophysics

Thousands of exoplanets have been discovered to date, revealing an astonishing diversity of worlds beyond our solar system. Studying their atmospheres is a key step toward understanding their physical and chemical properties, their formation and evolutionary pathways, and ultimately their potential to host life. Atmospheric observations provide a unique window into these distant planets, allowing us to probe their composition, temperature structure, and dynamical and weather processes.

This bachelor project focuses on modeling spectroscopic observations of the atmospheres of hot exoplanets, which orbit their host stars at extremely close distances. A central component of the project will be the modeling of cloud formation in the atmospheres of hot Jupiters and hot Neptunes. Atmospheric clouds are known to obscure molecular features and to strongly modify observed spectra, posing both significant challenges and exciting opportunities for their interpretation. In particular, this project will investigate whether clouds can inhibit certain chemical species from reaching the uppermost atmospheric layers and from participating in atmospheric escape. Such a mechanism could have important consequences for both observations and long-term atmospheric evolution, potentially leading to the selective retention and gradual build-up of specific elements in the atmosphere over time.

 

Title:  Clouds, waves, and mountains on Mars
Supervisors: Elle Hanson (l.e.hanson@uva.nl), Alessandra Candian (a.candian2@uva.nl) Category: Observational astrophysics

Mars is famous for having a dry, dusty climate, but the atmosphere also features a wide variety of water ice clouds. Since clouds can only form under very specific atmospheric conditions, analyzing the morphology of clouds can provide us with insight into the weather in parts of the planet where we have few or no direct measurements. In this project, you will analyze imagery from NASA’s Mars Reconnaissance Orbiter spacecraft to determine the morphology of northern hemisphere lee wave clouds throughout a Martian year. Using these measurements, you will be able to infer weather conditions in a part of the planet that has never been visited by spacecraft. Requirements: basic knowledge of thermodynamics. Knowledge of image processing and programming are helpful but not required.

 

Title: Shedding light on the composition of mysterious icy clouds on Titan

Supervisor: Alessandra Candian (a.candian2@uva.nl)

Project Type: Observational Astrophysics

Titan, the largest moon of Saturn, is a place like nowhere else in the Solar System. It possesses a dense, nitrogen-rich atmosphere, very similar to the one on early Earth, where solar photons trigger the formation of organic molecules such as HCN, CH4 and others. These molecules freeze in the lower atmosphere, creating icy clouds which spectroscopy signatures detected by the CASSINI mission. In this project, you will analyze the spectra of Titan's lower atmosphere recorded by the Cassini mission using available spectroscopic databases with the goal to understand the composition of these icy clouds. Some knowledge of Python is useful.

 

Title: What is the effect of galactic cosmic rays on Titan's atmosphere?

Supervisor: Alessandra Candian (a.candian2@uva.nl)

Project Type: Experimental Astrophysics

Description: Titan, the largest moon of Saturn, has a quirky atmosphere: the icy clouds present there are made of hydrocarbons such as CH3CN and HCN rather than water. Galactic Cosmic Rays can penetrate the upper atmosphere and interact with these clouds, and it is unclear what their effect is. Do they just detroy the clouds? Do the create new molecules from the initial components of the clouds? In this project you will analyze spectrometry data from experiments do we hope can answer this specific question. Knowledge of python or any other programming language is useful. Chemistry knowledge is not required.

 

Title: A step closer to solving a century old mystery: investigating the link between diffuse interstellar bands and interstellar dust with HST and JWST

Supervisors: Sascha Zeegers (s.t.zeegers@uva.nl), Chuanyu Wei, Lex Kaper 

Project type:  Observational Astrophysics, Experimental Astrophysics

Abstract: Diffuse Interstellar Bands (DIBs) have been a mystery for over 100 years. These absorption features can be found in the spectra of almost every star and are linked to small molecules in the interstellar medium. Over 500 DIBs are observed from the optical to the near infrared, but only ~5 features have been successfully linked to buckminsterfullerene (C60+). Recent detection of dust features in the infrared show correlations between the DIBs and carbon infrared dust features (Wei et al. in prep). 

Observing massive stars may help to better understand the enigma of DIB carrier molecules. We can compare the signature of the DIBs to infrared dust features and other absorption features found in stellar spectra, such as the UV extinction feature and the more recently discovered Intermediate Scale Structures (ISS, Massa 2020). 

In this project, you will measure the Intermediate Scale Structures and compare them with diffuse interstellar bands, observed in the spectra of O and B type stars. You will use HST and JWST observations of O and B stars (Zeegers 2025). You will look for correlations between these features. Providing a link between DIBs, the ISS features, and the infrared carbon dust features provides an important step into solving the mystery of the carriers of DIBs. 

 

Title: XRISM/Resolve high resolution spectroscopy of supernova remnants

Supervisors:  Jacco Vink (j.vink@uva.nl) and Manan Agarwal

Project type: Observational Astrophysics

XRISM/Resolve is relatively a new high resolution X-ray spectroscopy mission. We are involved in the project and also ready published initial results. Here we propose a follow up study on some of the supernova remnants. These include targeting abundances of rare elements but also modelling the effects of the broad point spread function. For the project we will pick one out of three topics: Cas A (high velocity of Calcium, incorporating Cr, Mn lines in broad spectral decomposition), RCW 86 (a hunt for the  Ar/Ca supernova ejecta), W49B and the quest for understanding what causes recombining plasmas.

 

Title: Speeding up X-ray spectral modeling using  emulators for NEI models

Supervisors:  Jacco Vink (j.vink@uva.nl) and Manan Agarwal

Project type: Observational Astrophysics, Applied Data Science

The project will focus on machine learning  techniques such as auto-encoders and principal component analysis in order to speed up modeling of supernova plasma spectroscopy at high spectral resolution.

 

Title: Investigating spectral-spatial  mixing with XRISM/Resolve

Supervisors:  Jacco Vink (j.vink@uva.nl) and Manan Agarwal

Project type: Observational Astrophysics

XRISM/Resolve has a high spectral resolution, but poor spatial resolution. The result is that spectra between neighboring pixels are cross-contaminated. In this project we will investigate what the effects are on the model published so far, and develop methods to reverse the effects of this spectral-spatial mixing.

 

Title: Are supernova remnants embedded in stellar clusters?

Supervisors:  Jacco Vink (j.vink@uva.nl) and Manan Agarwal

Project type: Observational Astrophysics

Massive stars are born in stellar clusters, and once a massive star has exploded and becomes a supernova remnant, the star’s siblings should still be around. However, there is surprisingly little known about the stellar clusters that should surround supernova remnants. In this project we will use GAIA data to investigate whether some supernova remnants are embedded in stellar clusters.

 

Title: Investigating the diffuse X-ray emission in the stellar cluster Westerlund 1

Supervisors:  Jacco Vink (j.vink@uva.nl) and Manan Agarwal

Project type: Observational Astrophysics

Westerlund 1 is one of the most energetic stellar clusters, containing 17 wolf-rayet stars. The winds from the massive star create a hot plasma that is slowly expanding into a cluster wind. For this project you will analyze this diffuse X-ray emission and see whether the plasma is out of ionization equilibrium. This will inform us how old the plasma is and how quickly the plasma is replenished.

 

Title:  Big data processing in radio astronomy: a machine learning approach for filtering images in real-time

Supervisor: Lars Zwaan, Antonia Rowlinson (b.a.rowlinson@uva.nl)

Project type; Observational Astrophysics, Applied Data Science

Modern radio interferometers like the Low Frequency Array (LOFAR) and the Square Kilometre Array (currently in development) constantly produce huge amounts of data. For example, LOFAR produces 13 Tbit/s of raw telescope data. As this is far too much data to analyse (or even transport!), several stages of automated data processing have been implemented, delivering science-ready data products to scientists. Currently, our group is trying to take this automation a step further. In addition to the data products (in our case, images of the radio sky) being produced in an automated way, we are developing methods to also analyse these images automatically. Specifically, we are interested in finding radio transients. Radio transients are flashes of radio light produced by a wide range of objects, including white dwarfs and neutron stars. These can have very short durations, like for instance fast radio bursts (FRBs), or take a bit longer, such as the recently discovered class of long period transients (LPTs). We are currently developing a method that allows us to search for these kind of radio transients in the constant stream of images that we will be producing in real-time with LOFAR. In order for this to work properly, we need to check the quality of each image before deciding whether we want to search it for transients or not.

The goal of this project is to investigate whether machine learning can be used for the quality-assessment of these images, and to develop an initial machine learning model for this.  As the focus of this project is on programming and machine learning, some background in these topics is preferred. Prior experience would come in handy, such as from the courses in artificial intelligence, machine learning or scientific programming offered by the programming lab at UvA. Any required skills and knowledge in radio astronomy and transients can be obtained during the project. If you want to learn more about the project and if it suits you, come talk to us!

 

Title: Fast imaging for transient searches with LOFAR2.0

Supervisor: Antonia Rowlinson (b.a.rowlinson@uva.nl ), Kate Kelley

Project type:  Observational Astrophysics

Since ancient times, astronomers have been interested in the changing astronomical sky. Variability studies initially started in optical, finding sources like supernovae and variable stars. As new facilities came online, astronomers were able to extend their studies to multiple wavelengths – from gamma-ray to radio. We now know that our Universe is highly dynamic and the sources we observe enable us to probe fundamental physics. We have now entered the information age, where multi-wavelength facilities are able to obtain vast amounts of data that can be searched for transients.

LOFAR is a low frequency radio telescope centred in the Netherlands and spread out across Europe. Our team has led the drive to search for radio transients with LOFAR over the past decade and we have developed key processing strategies to find new and exciting sources. LOFAR is currently undergoing a massive upgrade, with new computer hardware and automated processing.  LOFAR2.0 will begin operations this year and our team will, for the first time, run a new fully automated fast imaging and transient detection pipeline on all the observations from LOFAR2.0.

In this project, we want to try out our new automated pipelines on some of the very first data taken by LOFAR2.0. We will make 8 second snapshot images of the radio sky and process them with our new transient detection pipeline. We will then quantify transient and variable behaviour in the field and further analyse transient candidates to determine their progenitors. Knowledge of Python would be very useful. 

 

Title: Characterising radio transient candidates in LOFAR data

Supervisors:  Ziggy Pleunis (z.pleunis@uva.nl) with daily supervision by Inés Pastor-Marazuela (ines.pastor.marazuela@gmail.com), Reshma Anna-Thomas (thomas@astron.nl) and Sylvain Ranguin (s.l.ranguin@uva.nl)

Project type:   Observational Astrophysics

Fast radio bursts (FRBs) and long period radio transients (LPTs) are two novel classes of fast (milliseconds--minutes) radio transients with disputed origins, though most theories have them produced by different configurations of neutron stars and white dwarfs, isolated or in binary systems. We have been using snapshot images from the LOFAR telescope to search for "slow" FRBs and LPTs. In this project, the student will work on characterising radio transient candidates detected in LOFAR images by cross-matching them with multi-wavelength datasets. The student will also work on improving the transient detection pipeline. This is an opportunity to get experience with radio data analysis using a state-of-the-art large sky survey using one of the world's most sensitive radio telescopes and to become an expert on multi-wavelength astronomy.

 

Title:  Characterising fast radio burst variability through high-cadence monitoring campaigns

Supervisors:  Ziggy Pleunis (z.pleunis@uva.nl) with daily supervision by Dirk Kuiper (d.kuiper@uva.nl)

Project type:  Observational Astrophysics

In this project, we will characterize fast radio bursts (FRBs) as a function of time and radio frequency as part of our ongoing monitoring campaigns of repeating sources using various sensitive radio telescopes worldwide. FRBs are now known to originate in distant galaxies, but their physical nature remains mysterious. The short durations and extreme luminosities imply a compact source and high energy density. For that reason, most models focus on a neutron star or black hole progenitor - with the magnetically powered neutron stars known as "magnetars" being a particularly compelling model. However, both repeating and apparently non-repeating FRB sources are known, and we've found FRBs in a variety of surprising environments. Can they all be from magnetars, or is the mystery even richer than a single source model can explain? This project is ideal for a student interested in high-energy astrophysics and data analysis. They will gain hands-on experience with Python-based radio astronomy tools and linking observations to theoretical predictions.

 

Title:  Characterising the fast radio burst spectrum between the CHIME telescope and the Nancay and Effelsberg radio telescopes

Supervisors:  Ziggy Pleunis (z.pleunis@uva.nl) with daily supervision by Danté Hewitt (d.m.hewitt@uva.nl)

Project type:  Observational Astrophysics

In this project, we will characterize fast radio bursts (FRBs) as a function of time and radio frequency as part of our ongoing monitoring campaigns of repeating sources using various sensitive radio telescopes worldwide. FRBs are now known to originate in distant galaxies, but their physical nature remains mysterious. The short durations and extreme luminosities imply a compact source and high energy density. For that reason, most models focus on a neutron star or black hole progenitor - with the magnetically powered neutron stars known as "magnetars" being a particularly compelling model. However, both repeating and apparently non-repeating FRB sources are known, and we've found FRBs in a variety of surprising environments. Can they all be from magnetars, or is the mystery even richer than a single source model can explain? Here, we will start from an existing log book of all observations and detections from the CHIME/FRB survey and our high-cadence monitoring of CHIME sources using the Nancay and Effelsberg radio telescopes, and determine the chromatic activity of the FRBs that we have monitored. The student will gain skills in data analysis with Python, and will interpret the results in the context of theoretical models for the emission and immediate environment of FRB sources.

 

Title: Preparing for Atmospheric Science with an Upcoming Ground-Based Astronomical Near-UV Telescope Supervisor: Rudy Wijnands (R.A.D.Wijnands@uva.nl)

Project type: Observational Astrophysics, Instrumentation

We are building a new ground-based near-UV telescope, expected to become operational in about a year. This facility, optimized for near-ultraviolet (NUV; 300-350 nm) observations, will support both astronomical and atmospheric research. The project will explore the telescope’s potential for studying ozone layer variability and auroral emissions, expanding its use beyond traditional astronomy. The NUV sensitivity of the telescope makes it ideal for investigating how Earth’s atmosphere interacts with solar and cosmic radiation. NUV light triggers photochemical reactions critical for ozone dynamics, and auroral emissions arise from energetic solar wind particles interacting with Earth’s magnetosphere, providing insight into magnetospheric processes.

 

Project Details

· Telescope context and applications: The student will explore the scientific potential of the NUV telescope for atmospheric studies, focusing on the physical processes in ozone layer dynamics and auroral emissions, as well as its role in future astronomy observations.

· Ozone layer studies: Study the interaction of near-UV radiation with the ozone layer, focusing on photodissociation and its role in ozone variability. The student will assess how the telescope can monitor nocturnal ozone depletion and recovery, complementing satellite data.

· Auroral emissions in the NUV: Investigate the origin of auroral emissions in the NUV, including solar wind particle interactions with the atmosphere, and evaluate how the telescope can provide insights into energy deposition and ionospheric heating.

· Actual work: The student will conduct a literature review and explore the underlying physical models related to ozone layer dynamics and auroral emissions. They will also develop observational strategies, calibration methods, and data collection techniques for the telescope’s future use in atmospheric studies. Additionally, the student may identify potential improvements or modifications to the telescope’s design to better suit atmospheric studies without compromising its astronomical capabilities.

· Independent research focus: The student will select one of the two main themes (ozone or auroral emissions) for independent research, guided by the supervisor.

· Collaboration: The student will participate in weekly one-on-one meetings with the supervisor to discuss progress and delve into atmospheric and magnetospheric physics. Additionally, the student will contribute to team discussions and group meetings, fostering collaboration within the research group.