Examples of PhD projects available
An overview
There are currently several PhD positions open for application with a deadline of December 16, 2011. For details of the application procedure see this page. The positions are available in all the research areas in which the Observatory is active. This page gives a broad overview of possible research projects . However, research in different areas is possible and not all projects that might be offered are listed. The faculty research interests and the general overview of the research at the Observatory provide more background information.
- Galaxy formation, Theoretical
The group led by Joop Schaye has an opening for a PhD student to work on the formation of galaxies and the evolution of the intergalactic medium. The project will involve the analysis of the EAGLE simulation, a ground-breaking cosmological, hydrodynamical simulation using more than 10 billion particles that will be finished in 2012. The PhD student will become part of an international team. - Constraints on Reionization and Distant Clusters, Observational
The Dutch-European radio telescope LOFAR will open up the last unexplored window of the electromagnetic spectrum for astrophysical studies and make important contributions to our knowledge of the formation of structure in the universe. PhD positions with Huub Rottgering are available for the following three topics:- Forming massive galaxies at the epoch of reionisation. LOFAR will detect radio galaxies at unprecedented distances close to or even at the epoch when the universe makes a phase transition from neutral to ionised. LOFAR radio spectroscopy targeting associated neutral hydrogen 21 cm absorption would, for the first time, determine physical characteristics of the gas at this crucial epoch. Studies of these galaxies will constrain models of how massive galaxies and associated massive black holes are formed.
- Diffuse synchrotron emission associated with the first bound clusters of galaxies. Currently, diffuse radio synchrotron sources are known in about 50 nearby massive galaxy clusters. LOFAR has the potential to detect 10,000 of these systems, up to an epoch when the first bound clusters appear. Studies of the associated shock waves produced by cluster mergers and magnetic field properties of the cluster gas will constrain models of the formation of galaxy clusters.
- Star formation processes in proto-clusters. LOFAR will detect radio emission from millions of star-forming galaxies at an epoch at which the bulk of galaxy formation is believed to occur. In combination with infrared surveys, the first significant sample of proto-clusters of galaxies will be obtained. This will enable studies of how the physics of star formation differs between proto-clusters and the field.
- Extrasolar Planets - Observational
Ignas Snellen has -possibly- two openings for a PhD position to work on observations of extrasolar planet atmospheres. The projects involve ground-based measurements using the largest telescopes in the world to determine the atmospheric gases and temperature structure of gas giant planets. - Observations of Galaxies at Intermediate Redshift
The group of Jarle Brinchmann has an opening for working on the resolved properties of galaxies out to z=1. The core of the project will focus on the wealth of data coming from the MUSE Guaranteed Time Observations. MUSE is a new instrument for the VLT that will enable resolved spectroscopy of large numbers of galaxies. The PhD student will be closely involved in carrying out the observing and the analysis of intermediate redshift galaxies. - Study of dark matter and dark energy using weak gravitational lensing
Weak gravitational lensing by large-scale structure is one of the most promising probes to learn more about the nature of dark matter and dark energy. Pushing this field forward is one of the major goals of a new survey, the Kilo Degree Survey (KiDS), of which Prof. Konrad Kuijken is the PI. This project will survey 1500 square degrees in many filters over the next three years. To achieve the full statistical power of the survey, however, requires that we can measure the shapes of distant galaxies with high accuracy and interpret the measurements correctly.
Improving and implementing shape measurement methods developed in Leiden (and elsewhere within our international collaboration) will be a major part of a PhD project in the weak lensing group led of Henk Hoekstra and Konrad Kuijken. The PhD student will apply the resulting method(s) to data from KiDS with the aim to study the mass distribution around galaxies. A second PhD position focusses on the correct interpretation of the measurements. A simple interpretation of the lensing signal assumes that the orientation of galaxies is random in the absence of lensing. There are indications that this may not be the case, and the KiDS data are ideal to study these "intrinsic alignments" using real data. This will be the topic of this PhD position, which will also involve developing a physically motivated model, which can be compared to the data. - ALMA studies of protostars and protoplanetary disks
Two PhD positions are expected to be available in the group of Ewine van Dishoeck to study the physical and chemical evolution of protostars and protoplanetary disks using data to be obtained with ALMA. The ALMA data will be complemented by (existing) Herschel and VLT observations to probe a large range of physical conditions and to study molecules like water and methane that may eventually become part of exo-planetary systems. One project will focus on observations, whereas the other project will be centered around models. The PhD students will be part of an international team. - Computaional Astrophysics
The research group for Computational Astrophysics Leiden (CAstle), led by Simon Portegies Zwart, aims at studying the universe by means of simulation. The specific areas of research in astrophysics include the evolution of binary (and higher order multiple) stars, the dynamical evolution of dense stellar systems and of galactic nuclei. From a computational point of view the research group aims at simulation environments for solving the equations for gravitational dynamics, stellar structure and evolution, hydrodynamics and radiative transfer. Calculations are performed on computers built by the research group using graphical processing units, supercomputers and grid environments. Many simulations are carried out within the AMUSE software environment. The PhD project's objective is to study the interactive processes between the four mentioned physical domains. Topics of study will be related to the evolution of dense stellar systems, and in particular the interaction between the four mentioned physical domains; gravity, stellar evolution, hydrodynamics and radiative processes. Topics of study include the formation process and early outgassing of young and massive star clusters, the formation and stability of planetary systems, the importance and observability of black holes in star clusters. The calculations will be run on a cluster of graphical processing units (http://littlegreenmachine.org) using the AMUSE software environment. The available positions require frequent interactions within the research team and with international collaborators (in particular in the USA and Japan). Successful candidates should have an Master degree in computational science, astrophysics or a related field. Experience in software development and programming in Python/C/C++/MPI/CUDA are an advantage, as is an interest and experience in galaxy evolution, the dynamics around super-massive black holes and computational gravitational dynamics in general. The research will be conducted as part of the research group for Computational Astrophysics in Leiden and under direct supervision of Prof. Simon Portegies Zwart. - Structure formation in a warm dark matter universe.
Although hot dark matter (e.g. the standard model neutrinos) is disfavored by cosmological observations, warm dark matter (e.g. sterile neutrinos) is compatible with all observations and may in fact be required to explain the structure and abundance of dwarf galaxies. While the difference between warm and cold dark matter is small from a cosmological point of view, it is of crucial importance for particle physics, as it could imply a huge difference in the properties of the corresponding particle and could have impact on some very fundamental questions. Sterile neutrinos are strongly motivated from a particle physics point of view and astronomical constraints on their properties allow a systematic experimental program including accelerator and other direct searches.
As part of the framework of the de Sitter program in cosmology, Alexey Boyarsky and Joop Schaye are working on numerical modeling of structure formation in a universe with decaying dark matter particles that have significant primordial velocities with a non-thermal spectrum, as is expected for sterile neutrinos. The overall aim is to produce reliable predictions that can be checked with the data of upcoming weak lensing surveys, quasar absorption line data, and other tracers of structure formation on intermediate scales.