PhD position Kapteyn Astronomical Institute (6.0 FTE)

PhD position Kapteyn Astronomical Institute (6.0 FTE)

Published Deadline Location
28 Oct 1 Dec Groningen

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The Kapteyn Astronomical Institute of the University of Groningen invites applications for 6 PhD positions:

• One position in the group of Prof. Léon Koopmans (Kapteyn) on the localization and study of gravitationally-lensed gravitational waves from black-hole mergers.


Job description

The Kapteyn Astronomical Institute of the University of Groningen invites applications for 6 PhD positions:

• One position in the group of Prof. Léon Koopmans (Kapteyn) on the localization and study of gravitationally-lensed gravitational waves from black-hole mergers.

Both strong gravitational lensing and gravitational waves are consequences of General Relativity and were already predicted by Einstein himself. Whereas the first strong lens system was discovered some forty years ago, gravitational waves - from merging intermediate-mass black holes - have only been observed in 2015 for the very first time, leading to a Nobel Prize.

Although a lot can be learned from gravitational-wave data alone, no electromagnetic radiation is emitted if they result from two black holes merging. This absence of emission makes the event emission genuinely dark. With current gravitational detectors, it is also impossible to localise them to better than a few degrees of precision on the sky inside which thousands of plausible host galaxies of this event can be found. This positional information, however, is invaluable for many astrophysical and cosmological applications, such as their formation process, measuring the Universe's expansion rate, and more. Localising these events to better than an arc-second, one to ten-thousand times better than is currently possible, is therefore crucial.

The PhD candidate expands recent promising results, showing that strongly lensed gravitational-wave events can be localised to a fraction of the arc-second inside their host galaxies if they are strongly lensed by a foreground galaxy. The project will involve strong-lens simulations of gravitational wave events to study how precise they can be localised and what astrophysical and cosmological information can be extracted from such events, and also predict the rate of such events with the current and upgraded LIGO-Virgo-KAGRA laser-interferometer instruments in combination with deep optical and infrared sky surveys with upcoming space-based instruments such as Euclid and the Roman Space Telescope that will conduct deep wide-field surveys and can search for strong-lens systems. The project is carried out in the group of Prof. Koopmans (gravitational lensing) in Groningen, together with the group of Prof. van den Broeck (gravitational waves) in Utrecht and be connected to the LIGO-Virgo-KAGRA and Euclid consortia and be compared to their data. The candidate will be based in Groningen.

• Two positions in the group of Dr Tim Lichtenberg (Kapteyn) to simulate the evolution of magma ocean interiors and atmospheres for the interpretation of exoplanet data.

What are the best observational markers to test the physics of exoplanetary evolution and atmospheric diversity? Which prospects for plate tectonics have super-Earth exoplanets? What makes the difference between lifeless and potentially habitable worlds? Current and near-future exoplanet surveys deliver ever-more accurate insights into the atmospheric and surface conditions of rocky planets that are potentially similar to Earth in a number of features. As part of the expanding Forming Worlds research group at Kapteyn, you will model the interaction of atmospheric volatiles with exoplanetary interiors, applicable to hot magma ocean epochs, such as on short-period exoplanets and the prebiotic Earth. The first project will focus on the atmospheric evolution of exoplanet climates, while the second project will center on the geophysics of planetary interiors. More detailed information can also be found at:

• One position in the group of Prof. Karina Caputi (Kapteyn, together with Dr Edoardo Iani) to unveil the star-formation histories of high-redshift galaxies.

The presence of emission lines in galaxy spectra is typically a signature of on-going star-formation activity. Many high-redshift galaxies are line emitters, but in the majority of cases little is known about the underlying stellar populations co-existing in these galaxies. Are these galaxies purely young, or are young and old stellar populations simultaneously present? In this project the PhD candidate will study different aspects of this problem by combining spectroscopic and photometric data from world-class observatories, particularly the JWST and VLT. The goal is to constrain the complex star-formation histories of high-z star-forming galaxies and compare with predictions of galaxy formation models.

• Two positions in the group of Dr Harish Vedantham (ASTRON/Kapteyn) to work on the topic of exoplanet radio astronomy.

The aim of these two PhD positions is to study space-weather phenomena around exoplanets using radio observations. The two PhD projects are funded via the ERC starting grant of Dr. Vedantham and they respectively involve (a) searching for radio emission from gas-giant exoplanets with an aim to achieve the first direct detection of magnetic fields on an exoplanet and (b) searching for characteristic radio bursts from nearby stars associated with coronal mass ejections that can have a detrimental effect on exoplanet atmospheres. The candidates will join Dr Vedantham’s young and growing research group which is pioneering the use of novel low-frequency radio telescopes such as LOFAR for stellar, brown dwarf and exoplanet research. The candidate will be based at, and graduate from, the Kapteyn Astronomical Institute of the University of Groningen. The candidate will also make regular visits to ASTRON, the Dutch radio astronomy institute. ASTRON led the design and construction of the LOFAR telescope and is playing a leading role in the upcoming Square Kilometre Array project. We seek candidates with excellent communication skills in English (written and verbal), evidence of research interest, and computer programming experience. Prior experience with either radio astronomy techniques and/or high-performance computing is a key advantage, but not strictly necessary.

The Kapteyn Astronomical Institute is part of The Netherlands Research School for Astronomy (NOVA) and is recognised worldwide for the quality of its research in multiple areas of astronomy. With 15 faculty and 50 PhD students, it is the second-largest astronomical institute in The Netherlands. Groningen, a historic town in the northern Netherlands, occupies a strategic place in Dutch astronomy, hosting both the Kapteyn Astronomical Institute, the low-energy astrophysics division of the Netherlands Institute for Space Research (SRON) and the NOVA sub-mm lab. The Kapteyn Institute has a strong connection with the Netherlands Institute for Radio Astronomy (ASTRON) in Dwingeloo, a European centre of radio astronomy research. Staff and PhD students at the Kapteyn Institute frequently collaborate with SRON and ASTRON scientists and engineers. There are also strong interdisciplinary connections with other institutes in the Faculty of Science and Engineering, and the Dutch Origins Center. English is the common language spoken at the institute.

For detailed questions about a particular project, please email the prospective supervisors:


University of Groningen


We seek excellent students with a strong background in the physical sciences who desire to obtain a PhD degree from a top European university. A successful candidate must hold a Masters degree in Physics, Astronomy or a related field, or equivalent by the starting date of the position. Previous research experience and computational skills will be important criteria for the selection.

Conditions of employment

Fixed-term contract: 48 months.

These PhD positions are paid according to the Collective Labour Agreement of Dutch Universities (CAO), which means that they earn internationally competitive salaries (the current annual gross salary, including allowances, increases from about € 35,000 in year 1 to about € 44,800 in year 4) and are eligible for both social security and retirement benefits. All PhD positions are funded for four years.


Faculty of Science and Engineering

Groningen ( is a historic university town in the northern Netherlands with a population of approximately 230,000 people, of which almost 25% are students. This makes Groningen the city in The Netherlands with the highest student population density, the youngest city in the country, and one of the youngest in Europe. Groningen offers very high quality of life, surrounded by beautiful nature, and is a lively city with a remarkably diverse cultural scene. You can find more information on


  • PhD
  • Natural sciences
  • University graduate
  • 222730-35


University of Groningen

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Broerstraat 5, 9712 CP, Groningen

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