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In het derde bachelorjaar kunnen studenten een onderzoeksproject doen van 15 ECTS tussen februari en augustus. Bij interesse in een project en voor meer details, kunnen studenten contact opnemen met de supervisor van het project.

1.  Growing the planets by Pebble Accretion

Supervisors: Rico Visser, Carsten Dominik
Contact:  r.g.visser@uva.nl

The stages of planet formation encompass a factor 10^40 mass increase from the smallest dust grains to the gas giants such as Jupiter and Saturn. Throughout these stages many physical processes play a role. Even today, coming up with a consistent theory that matches observational data from young protoplanetary disks remains challenging. For example, we encounter growth barriers already in the early stages of planetary growth. Classical planet formation scenarios such as core accretion have difficulty growing a planet within the lifetime of the gaseous protoplanetary disk.

One promising new theory to overcome planetary growth barriers is Pebble Accretion. In Pebble Accretion a small planetoide/asteroide (read body) is sweeping up small ‘pebbles’ in the young gaseous protoplanetary disk. It turns out that the gas damping produces large collision cross-sections for these small bodies since the gas slows down the pebbles in an encounter. The conspiracy between the small body’s gravity and the disk gas can lead to fast growth of the small body well within the disk lifetime. Further information on Pebble Accretion can be found here: https://www.nemokennislink.nl/publicaties/waarom-planeten-in-dezelfde-richting-draaien/

In this project you will build a basic model of pebble accretion. You will investigate the (hydro)dynamics of the pebbles in a protoplanetary disk around a star with the presence of gas and a small planetoide. The goal of this project is to understand when a pebble will be captured by the planetoide and when it will be lost to the gas. Parameters of interest following from this analysis might be orbit classification, growth rate of the planetoide and spin rotation.

For more information about this project you can contact:

Msc Rico Visser, mail: ​r.g.visser@uva.nl Prof dr. Carsten Dominik, mail: dominik@uva.nl

Prof. dr. C. (Carsten) Dominik

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

2.  Investigating the UV variability of stars in Galactic globular clusters

Supervisors: David Modiano, Aastha Parikh, Rudy Wijnands

Abstract: The sky is very variable at all electromagnetic wavelengths and has been intensively studied at all time scales. However, one understudied regime is the ultraviolet (UV). This is mostly because the UV is absorbed by the Earth's atmosphere and space-based instrumentation is prohibitively expensive, i.e., instruments with very large field-of-view (FOV). However, small FOV instruments are available, i.e., the UV and optical telescope (UVOT) aboard the Swift satellite. In this project, we will utilize the UVOT to study the UV variability of stars in Galactic Globular clusters.  These stars can range from accreting white dwarfs to periodic variables like RR Lyrae stars. The project will start by using the more than 100 UVOT observations we already acquired from the globular cluster NGC 2808 but other clusters might also be included if time permits.

Prof. dr. R.A.D. (Rudy) Wijnands

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

3.  Searching for fast (<1 minute time scale) to very fast (second) optical transients

Supervisors: Rudy Wijnands, David Modiano, Aastha Parikh
Contact: r.a.d.wijnands@uva.nl

Abstract: The optical sky can be very variable (i.e., called transients), with many different source types (e.g., supernovae, gammay-ray bursts, accreting white dwarfs, flare stars, interacting binaries) exhibiting several to many orders of magnitude variability in the optical. Therefore, many sky surveys are currently active or in design to search and study such transient sources. However, nearly all surveys prober the long to very long time scales of hours to days to weeks, and only a small number of surveys can probe timescales down to a few minutes. Moreover, sub-minute (i.e., seconds) timescales are hardly probed. Therefore, we have designed a studentproject (a pilot study) to use a run-off-the-mill CMOS camera to survey the fast (<1 minute) to very fast (seconds) timescales of the optical sky. The oservations will be done at night by the student using a mobile 10 cm telescope and with the fixed telescopes in the domes on SP 904. Expected targets are prompt emission from explosive events like gamma-ray bursts and supernovae explosions, down to fast variability from flare stars, and potentially unknown types of sources.

Prof. dr. R.A.D. (Rudy) Wijnands

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

4.  Evolutionary modeling of magnetic binary stars

Supervisor: Zsolt Keszthelyi
Contact: z.keszthelyi@uva.nl

Description: Hot, massive stars are crucial building-blocks of the Universe. Some of these stars possess detectable surface magnetic fields which can greatly influence their evolution. Although binarity is common amongst massive stars, it turns out that magnetic fields are very rare in massive star binary systems and only a handful of them are known. 

Objectives: The main objective of the project is to perform computations of evolutionary models representative of known magnetic massive star binary systems, aiming to reconcile the models with observables. The student will gain experience in computing models with a state-of-the-art stellar evolution code, learn about massive star evolution, binarity, and surface magnetic fields. 

5.  Explaining the self-regulation of star formation

Supervisor: Sam Geen (http://samgeen.com/)
Contact: s.t.geen@uva.nl

The primary part of the project is to push this quantitative understanding of how feedback shapes star formation. You will build a model for the lifecycle of a star-forming region using existing physical building blocks. You will compare this model with high-resolution hydrodynamic simulations, and use it to make wider predictions for how feedback shapes the universe. In a secondary part, you will work with the stellar evolution team at API to understand how interactions between stars have consequences for these larger scale phenomena.

s.t.geen@uva.nl. Women or people from underprivileged backgrounds are encouraged to apply.

Dr. S.T. (Samuel) Geen

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

6.  Mapping the surfaces and interiors of neutron stars

Supervisor: Anna Watts
Contact: a.l.watts@uva.nl

NICER, the Neutron Star Interior Composition Explorer, is an X-ray telescope that was installed on the International Space Station (ISS) in 2017. Its mission is to study the nature of the densest nuclear matter in the Universe, found in the cores of neutron stars.  To do this NICER exploits relativistic effects on X-rays emitted from the hot magnetic polar caps of millisecond pulsars.   The technique also lets us map the hot emitting regions, which form as magnetospheric particles slam into the stellar surface. First results from NICER have been very surprising in terms of the hot spot geometry, and how this affects our ability to measure the dense matter properties that are the mission's primary goal.  In this project you will explore these issues further, using the relativistic ray-tracing code that we are using in our analysis of NICER data.  The goal will be to understand and reduce potential sources of error in our analysis.  The project will be primarily theoretical in nature, but driven directly by the latest results that we are obtaining from the ISS.

Prof. dr. A.L. (Anna) Watts

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

7.  Modeling the dust and gas in the HD100546 disk across all ALMA scales and wavelengths

Supervisor: Michiel Hogerheijde (API & Leiden Observatory)
Contact: M.R.Hogerheijde@uva.nl

The planet forming disk around the star HD100546 has received a lot of attention due to its brightness and the spectacular inner (~10 au) clearing that could be a signpost of the presence of a (proto)planet. ALMA has observed this disk at wavelengths between 3 and 0.3 mm and from scales of a few au out to 400 au and more. Several papers in the literature describe the small-scale structure of this disk, but surprisingly little work has been done on its large scale structure: To what distance from the star do gas and dust extend? What is the surface density distribution? In this project we will combine the available ALMA data to construct a single model describing the various scales and wavelengths, to arrive at the most comprehensive description of the HD100546 disk possible.

During this project you will develop a basic understanding of star and planet formation, as well as the structure of and processes occurring in planet forming disks. You will acquire a basic understanding of interferometry and radiative transfer, and extensively use python programming. 

Prof. dr. M.R. (Michiel) Hogerheijde

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

8. TeV gamma rays from ultrahigh energy cosmic rays

Supervisors: Dmitry Prokhov, Jacco Vink
Contact: J.Vink@uva.nl

Abstract: Ultrahigh-energy cosmic rays (UHECRs) are the most energetic particles 
in the Universe. The origin of UHECRs has been an unanswered biggest mystery.
In 2018  the Pierre Auger Observatory provided evidence for anisotropy in the arrival
directions of UHECRs on an intermediate angular scale, which is indicative of excess
arrivals from strong, nearby sources. Among the most likely sources are Starburst
galaxies, including NGC 4945, and radio galaxies, including Centaurus A and Fornax A. Secondary photon fluxes in the TeV energy band originated from UHECR interactions with the CMB have been discussed in the literature and their detectability with imaging atmospheric Cherenkov telescopes, especially with H.E.S.S., has been predicted. Given new observations of these sources with the H.E.S.S. telescope, the efforts are needed to compare their results of with the models.  For the bachelor project, the student will model the TeV emission created in the interaction of UHECRs from nearby sources with the CMB. During the project, the student will build knowledge of and skill in the scientific process.

Dr. J. (Jacco) Vink

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

9.  X-ray analysis of the supernova remnant N63A 

Daily supervisor: Lei Sun (+ Dmitry Prokhov); supervisor: Jacco Vink
Contact: J.Vink@uva.nl

This supernova remnant is a bright, older (several thousand year) object in the
Large Magellanic Cloud. It recently got our groups attention as it may also
be a gamma-ray source, a sign of the presence of cosmic rays inside the remnant.
In order to better understand the gamma-ray properties we need to know the
parameters of the source, for which we can best use existing X-ray data.
For the bachelor project the student will analyse the existing Chandra (imaging)
and XMM data (spectroscopy) in order to better constrain the age, density and
temperature of the supernova remnant.

Dr. J. (Jacco) Vink

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

10.  Observational Astronomy with the Anton Pannekoek Observatory

Supervisor: Rasjied Sloot
Contact: M.R.Sloot@uva.nl  

The student will gather (most of) his or her own data using telescopes and instruments available in our Observatory.

Students can come up with their own research topic. A few suggestions are:

Exoplanet transits: determining orbital parameters of planetary systems
Determine stellar properties of pulsating stars
Eclipsing binaries: modeling stellar properties
Determining the age and distance of open clusters of globular clusters
Measure the redshift objects at large distances

Solar topics:
High-resolution spectroscopy of the sun using the APO Heliostat

M.R. (Rasjied) Sloot MSc

Faculteit der Natuurwetenschappen, Wiskunde en Informatica

Anton Pannekoek Institute of Astronomy

11.Predicting coherent radio emission from GRBs 

Supervisors: Kelly Gourdji, Antonia Rowlinson
Contact: k.gourdji@uva.nl

Following the most powerful explosions in the Universe, Gamma-Ray Bursts (GRBs), there is a bright multi-wavelength afterglow. Often in the X-rays we see a plateau phase which is powered by the central engine – either a massive neutron star (referred to as a magnetar) or a black hole. Assuming a massive neutron star is formed, low frequency coherent radio emission may be emitted and be detectable by LOFAR (The Low Frequency Array; a radio telescope centered in the Netherlands).

This project aims will create, using a Monte Carlo sampling strategy, a simulated population of magnetar central engines that would be observable by the Swift Satellite. Using various theoretical models, the coherent radio emission will be predicted using the simulated population and then compared to the observational capabilities of LOFAR. We aim to use these results in combination with observational data to rule out (or confirm) the theoretical models for coherent radio emission.