Find a PhD Project Here
Opportunities for fully funded PhD or EngDoc research projects are available in all fields of research within the School. You may search for current projects on this page. APPLY HERE for a PhD Place.
Search current PhD opportunities in the School of Physics & Astronomy:-
A main diagnostic of the particle dark matter is its annihilation rate, which depends sensitively on the dark matter density profile. The student will explore various density models of the dark matter, taking into account the effects of black holes and baryonic dynamics.
These projects will investigate the atmospheres of planets and Brown Dwarfs which contain the fingerprints of their physics and chemistry. Atmospheres of Brown Dwarfs and giant gas planets are forming clouds that can be made of silicate and iron dust rather than of water. Any clouds leave a trace of an individually depleted gas which determines the spectral appearance of the planet/Brown Dwarf as well as it does influence the dynamic behaviour of the atmosphere.
Using a detailed model of dust formation, possible topics include:
1) Atmosphere's response on planetary evolutionary events
like volcanism, dust/gas accretion, mass loss during star-planet interaction
2) Modeling atmospheres of planets/Brown Dwarfs in nearby galaxies,
like the Large and the Small Magellanic Cloud
3) Modeling planetary atmospheres under the influence of disk evolution
combining results from protoplanetary disk evolution model with atmosphere modeling
The bulges of disk galaxies play a central role in understanding galaxy evolution in general. For instance, their size is one of the main features by which galaxies are classified in Hubble types. In addition, bulges account for more than one quarter of the stars in the local Universe (Driver et al. 2007, MNRAS, 379, 1022) and influence the size and strength of bars (Sellwood 1981, A&A, 99, 362), which in turn have a profound effect on the rest of the barionic mass distribution. Bulges host central supermassive black holes (SMBH), which may regulate nuclear star formation (Springel et al. 2005, MNRAS, 361, 776), and the mass of the SMBH correlates with the velocity dispersion of stars in the bulge (Gebhardt et al. 2000, ApJ, 539, 13), suggesting that these objects of vastly different scales somehow regulate one another (but see Kormendy 2011, Nature, 469, 374).
Despite their importance, the formation of bulges is still poorly understood and questions such as how much of the observed morphology in disk-dominated galaxies is due to hierarchical buildup and how much due to internal evolution remain unanswered. In fact, the division between external vs internal formation is reflected in the two classes of bulges which are thought to exist: classical and pseudobulges.
Classical bulges can be formed via dissipative collapse of protogalactic gas clouds (Eggen et al. 1962, ApJ, 136, 748) or by the coalescence of giant clumps in primordial disks (Bournaud et al. 2007, ApJ, 670, 1179). In addition, they can also grow out of disk material externally triggered by satellite accretion during minor merging events (Aguerri et al. 2001, A&A, 367, 428) or by galaxy mergers (Kauffmann, 1996, MNRAS, 281, 487) with different merger histories (Hopkins et al. 2010, ApJ, 715, 202). Observationally, their surface-brightness distribution generally follows a De Vaucouleurs law (Andredakis et al. 1995, MNRAS, 275, 874). They appear rounder than their associated disks and their kinematics are well described by rotationally flattened oblate spheroids with little or no anisotropy (Kormendy & Illingworth 1982, ApJ, 256, 460). Finally, they have photometric and kinematic properties which satisfy the fundamental plane (FP) correlation (Bender et al. 1992, ApJ, 399, 462).
Disk-like bulges (pseudobulges) are thought to be the products of secular processes driven by bars (see Kormendy & Kennicutt, 2004, AAR&A, 42, 603). Bars are ubiquitous in disk galaxies. They are efficient mechanisms for driving gas inward to the galactic center triggering central star formation generally associated with a pseudobulge. Alternatively stars can be moved by a bar to the center, usually resulting in a boxy/peanut (B/P) bulge due to a coherent bending of the bar perpendicular to the disk plane (Debattista et al. 2004, ApJ, 604, 93). Observationally, pseudobulges have an almost exponential surface-brightness distribution (Andredakis & Sanders 1994, MNRAS, 267, 283), and height similar to their associated disks. Pseudobulges rotate as fast as disks and usually deviate from the FP (Carollo 1999, ApJ, 523, 566).
It is clear that a deep understanding of bulge formation requires determining the actual demography of classical and pseudobulges, and how these bulge types evolve during the galaxy lifetime. Thus far, most of the work in this field has used the 'fossil approach', i.e., analyzing in detail observations of bulges at z~0 and using stellar evolution and/or dynamical models to investigate the initial formation of the bulges at earlier times. The current project is about using the 'direct method', i.e., using Cosmology as a time-machine to observe and analyze the bulges in disk galaxies as a function of distance or look-back time. This approach has been rarely used in the past, mostly due to technical limitations that are now being solved thanks to new large surveys undertaken by the Hubble Space Telescope. The project will analyse data from the low-z Integral Field Survey CALIFA, the intermediate-z spectroscopic and photometric survey GAMA, and the high-z multiwavelength photometric survey CANDELS, which maps three different times in the evolution of the Universe, in order to identify and characterize bulge structures as a function of time.
The project involves the development of classification and analysis techniques for local galaxies (CALIFA) which will then be applied to more distant samples (GAMA and CANDELS). It may also involve the writing of observing proposals to obtain follow-up data on the most advanced telescopes in the world. While this is mainly an observational project, comparison with state-of-the-art numerical simulations, run on a dedicated supercluster by the galaxy evolution group at the University of St Andrews, will be required to understand the physical processes which lead to the formation and evolution of bulges.
This project will be joint supervised by Jairo Mendez-Abreu and Vivienne Wild as part of the EU funded SEDmorph collaboration. For more details, see the project pages here: http://www-star.st-and.ac.uk/~vw8/SEDmorph/welcome.html
Jardine, Prof Moira - firstname.lastname@example.org
Low mass (fully convective) stars appear to generate magnetic fields whose surface distributions are fundamentally different to those of higher mass stars. We will use existing Zeeman-Doppler maps of these surface magnetic fields to model the coronal structure and X-ray emission of these stars.
How galaxies form and evolve is one of the outstanding questions of modern astrophysics. Large surveys are providing an increasingly detailed census of both local and distant galaxies. Considerable progress is being made on quantifying the changing demographics of the galaxy population over the majority of the age of the Universe. Massive numerical simulations have revealed the “hierarchical” nature of structure formation, in the dark matter at least, with small dark matter halos coalescing to form larger gravitationally bound systems. Such simulations have had good success in reproducing the spatial distribution of galaxies observed in large surveys. However, the complex array of physical processes that affect baryons within the dark matter halos, (e.g. gas heating and cooling, star formation, feedback, torques and drag) has so far prevented us from building a comprehensive understanding of how and why galaxies grow and change over time.
This project is about understanding the physical processes responsible for changing galaxies from the irregular balls of gas observed at high redshift, into the bimodal population of star-forming spirals and quiescent ellipticals seen around us today.
In the last decade a Bayesian approach to the fitting of sophisticated models to high quality spectra and/or multiwavelength photometry has become common place in the analysis of galaxies at all redshifts (see Walcher et al. 2011 for a review). The comparison of models and data is a complex, but well-studied statistical and mathematical problem, and the simple Bayesian techniques used in the field of galaxy evolution can be substantially improved upon.
Empirical, or hierarchical, Bayes techniques are starting to appear in the astronomical literature to solve problems as diverse as QSO redshift estimation (Bovy et al. 2011), exo-planet orbit analysis (Hogg et al. 2011) and the properties of SN 1a light curves (Mandel et al. 2009). They differ from standard Bayesian methods by fitting the entire dataset in a coherent manner, instead of single objects using pre-defined priors. For galaxy evolution studies, this will improve our ability to break degeneracies.
This project will analyse data from two surveys: GAMA and CALIFA. For more information on these surveys see there websites:
This project is funded by the EU funded ERC starting grant held by Dr. Wild, is for a period of 3.5 years, and comes with substantial travel funds. The student will work within an active group of young and experienced researchers both within the University of St Andrews and around the world (UK, Australia, Germany, Spain, Finland).
The project involves the development of statistical techniques to make them applicable to astronomical datasets. Applications from students with a background in maths or physics and interest in astrophysics are welcome, as well as from students with a background in astrophysics but strong aptitude for maths and statistics.
For further information please see Dr. Wild's website or send her an email (http://www-star.st-and.ac.uk/~vw8/)
Bovy J., Myers A. D., Hennawi J. F. et al. arXiv:1105.3975
Hogg D. W., Myers A. D., Bovy J., 2010, ApJ, 725, 2166
Mandel K. S.; Wood-Vasey W. M., Friedman A. S., Kirshner R. P., 2009, ApJ, 704, 629
Walcher C. J., Groves B., Budavri T., Dale D., Ap&SS, 2011, 331, 1
Extensive layers of diffuse ionized gas are observed in the Milky Way and other galaxies. This project will study the structure, ionization, heating, and dynamics of diffuse ionized gas using a combination of 3D Monte Carlo radiation transfer codes and recent 3D dynamical models of a supernova driven ISM.
Light travel time delays enable micro-arcsecond mapping of accretion disks and broad emission-line regions around the super-massive black holes in the nuclei of active galaxies. RoboNet provides the UK with unique datasets for measurement of black hole masses, accretion rates, and luminosity distances. The student will acquire and analyse such datasets, using parameterized models and Hornes maximum entropy fitting code MEMECHO.
Most stars form in clusters, where energetic feedback from massive
(proto)stars--including outflows, ionization, heating, and
winds--shapes the environment and impacts accretion. The relative
importance of different feedback processes is a key outstanding
issue in our understanding of massive star formation.
The aim of this project is to conduct the first large-scale
observational study of the role and physics of feedback in massive
(proto)clusters. This will involve analyzing high-resolution data
from recently-upgraded (sub)mm and cm-wavelength interferometers, in
particular the Submillimeter Array (SMA), the Jansky Very Large Array
(VLA), and, potentially, the Atacama Large Millimeter/sub-millimeter
Array (ALMA). The observational results will be compared with
simulated observations of numerical models of massive star and
Current hydrodynamical models for planet formation and migration
suffer from a very basic uncertainty, namely the poor treatment of radiative transfer effects.
This project aims at the production of numerical look-up-tables for physically grounded, radiative heating and cooling rates suitable for hydrodynamical disc simulations, including equilibrium temperature structures and effective heating/cooling relaxation timescales. The calculation of the heating/cooling rates will be based on the radiation thermo-chemical disc code "ProDiMo", which includes a very detailed treatment of 2D continuum and line radiative transfer, and gas energy balance.
The task is to build a brigde between thermo-chemical and hydrodynamical disc simulations. The student will study and learn how to run both types of models, calculate the look-up-tables with ProDiMo, and then apply these in hydrodynamical disc simulations.
The ionisation of the atmosphere depends on the local temperature which, in turn, depends on the effective temperature. We will study how the atmospheric electrification changes with decreasing effective temperature from the M-dwarfs into the Brown Dwarfs into the planetary mass regime.
See also LEAP PhD positions
Wood, Dr Kenny - email@example.com
In very young stars, material accreting from a surrounding disk is channelled by the star's magnetic field onto the stellar surface. We will use recently-acquired magnetic maps of these stars to model the impact of magnetic cycles on this accretion process.
The mass distribution of the Galaxy is being / will be mapped out in great detail in the next decade with the numerous surveys of the Galaxy, including Segue, RAVE, GAIA, and completed ones like 2MASS, DENIS. A model for the potential and phase space of the galaxy is essential to bring various pieces of information together. The student will develop such models building on experience from existing models.
Intensive monitoring of Galactic Bulge microlensing events is being used to discover cool planets in 1-5 AU orbits around the lens stars. Our PLANET/RoboNet team has just discovered a 5 earth-mass planet. In the next 4 years we aim to measure the abundance and mass function of cool planets to test theories of planet formation and migration. The student will work with our team to acquire and analyse observations, fit microlens models to characterize the planetary and other anomalies.
This project is to develop the first models of resolved star formation on galactic scales. This will involve modelling a full galactic potential and how it drives the formation of molecular clouds and the onset of gravitational collapse and star formation. feedback from ionisation and supernova will be included to assess molecular cloud lifetimes and star formation efficiencies.
Tau Boo is the only star for which we have been able to track the full cyclic reversal of the stellar magnetic field. This system is also well-known, however, because it hosts a Hot Jupiter that is so close to the star that it may lie within the stellar corona. What is the nature of the interaction between the star and planet in this case and is it related to the puzzling nature of the very short magnetic cycle? This project will investigate tau Boo and other similar star-planet systems.
The faint outskirts of galaxies are still mostly unexplored regions, yet they contain valuable information about their formation history. In the outer parts of galaxies, the dark halo starts to dominate over the luminous matter (stars and gas). The composition of the stellar halo population, and its behaviour as a function of radius, provides constraints for the formation and merger history of galaxies.
In this project, we will use integral-field spectroscopy to map the dark and stellar haloes of early-type galaxies (ellipticals and lenticulars), and where possible, combine our spectroscopy with deep imaging and cold gas (HI) observations. The student will learn to analyse integral-field data, as well as techniques that deal with stellar population analysis and dynamical modelling.
Weijmans et al. 2009, MNRAS, 398, 561
Weijmans et al. 2008, MNRAS, 383, 1343
The primary supervisor of this project will be Anne-Marie Weijmans who will join us on the 1st July 2013 as a new temporary lecturer in Galaxy Evolution.
Wood, Dr Kenny - firstname.lastname@example.org
Understanding the structure, composition, and dynamics of protoplanetary disks are crucial for planet formation theories. This project will combine dynamical models of disks with 3D radiation transfer and new multiwavelength imaging. In particular, data from the high-resolution radio survey PEBBLES (an eMERLIN Key Project) will be used to measure grain growth and look for signs of rocks clumping together to make planetary cores, in the first few million years of stellar lifetimes.
With more than 400 planets orbiting stars other than the Sun known (as of March 2010), observing campaigns now need to evolve from the pure detection of planets to studies that allow to infer the statistical properties of the underlying populations that are being probed. Only by comparing a wide planet census with model predictions of planet formation and evolution, will we be able to understand the origin (and future!) of habitable planets, and Earth in particular. Due to their probabilistic nature, gravitational microlensing experiments are particularly challenging, but they are suited to provide insight that remains hidden to any other known technique, with a sensitivity reaching even below Earth mass, and the possibility to spot signatures of planets orbiting stars in other galaxies. The realisation of a fully-deterministic observing strategy is a necessary prerequisite for measuring planet abundances. Over the recent years, we have been working on the development of the world-leading technology for implementing an automated microlensing campaign that is carried out by means of our RoboNet-II and MiNDSTEp telescope networks, and informed about the targets to be observed by the publically-accessible ARTEMiS system. Two specific topics currently call for special attention:
1) Further development of ARTEMiS is required to provide a target recommendation for a non-proprietary heterogeneous network of telescopes according to a user-defined strategy, the currently available data, the individual telescope capabilities, and the observability. Gravitational microlensing is a showcase application for modern telescope scheduling, and by its strong demands on flexibility and reaction time leads to pioneering concepts that can be of far more general use. Moreover, ARTEMiS not only provides tools to astronomers, but also brings forefront science to the general public.
2) Imperfections in the data reduction lead to various types of spurious signals, which either need to be properly identified and separated from real variations, or to be treated statistically as a form of background noise. The low-mass sensitivity limit of our campaigns crucially depends on how well we understand this. Moreover, a proper understanding of false positives will make a difference on the efficiency of our monitoring programme by allowing more appropriate decisions based on real-time data.
Planets form in disks of gas and dust surrounding young stars. These
disks exhibit weather-like phenomena -- rapid structural and chemical
changes -- due to accretion bursts, instabilities, and magnetic activity.
So far, this disk weather is a neglected aspect of our theoretical
framework for planet formation. Disks are usually modeled as steady-state, slowly evolving entities. Recent results, however, including evidence from our own solar system, strongly suggests that rapid dynamical processes have a lasting effect on the disk evolution and the outcome of planet formation. Observationally, one of the most promising ways to study these processes is the analysis of the time-domain behaviour of young stellar objects (YSOs). This is the framework of the long-term program TOYS (Time-domain Observations of Young Stars), under the direction of new staff member and Observatory Director Dr Aleks Scholz.
As part of TOYS, we will investigate disk weather in a sample of variable
YSOs using a combination of photometric and spectroscopic time series,
spanning timescales from minutes to decades. In particular, we aim
to determine the physical origin of the variability, constrain the
physical conditions in the inner disks, and build simple time-dependent
models for YSOs. The project will be based on images and spectra
obtained with the ESO-VLT and the 1.3m telescope on Cerro Tololo.
The student will have the opportunity to carry out complementary
observations with the James Gregory Telescope in St Andrews.
There are several outstanding issues in current models of star formation. One of these is the role of feedback from young stars in producing subsequent generations of young stars. Triggering of star formation through supernova events is likely to be the dominant mechanism. Numerical simulations of SNII impacting on molecular clouds and the triggering of star formation will be used to develop physical models, and ultimately observational predictions and tests of the process.
The WASP project (http://www.superwasp.org) is a consortium comprising 6 UK universities and 3 overseas observatories. We use two arrays of wide-field camera lenses backed by large-format CCDs to perform high-precision photometry of millions of stars each night, looking for the 1% dips in light that betray gas-giant planets whose orbital planes are close enough to the line of sight that they transit their host stars. Our current catch stands at 98 planets confirmed by radial-velocity follow-up.
Possible components of a PhD project include:
- [New for 2013!] Developing new methods to use Gaia data products to improve the transit detection and pre-selection criteria for eliminating astrophysical and other false positives;
- Measuring stellar spin rates and spin-orbit misalignments using time-resolved spectroscopy during transits;
- Using high-resolution time-series transit spectroscopy to confirm the presence of planets around early-type stars;
- Determining the ages of transiting planet systems from the spin rates of the host stars;
- Modelling the tidal spin-orbit interaction between the closest-orbiting hot Jupiters and their host stars;
- Reconciling the planet catch with models of the galactic planet population and observational detection thresholds;
- Improving the quality of the SuperWASP photometry using image-subtraction and profile-fitting methods;
Specific project for Autumn 2013 intake:
The hot gas giant planets found by ground-based surveys such as WASP and HAT represent a population that is statistically rare but extremely informative about formation and migration processes. Indeed they are so rare that they are not represented in the Kepler planet catch at all! With the imminent launch of the Gaia mission, I am keen to develop a student project to make use of the superb astrometric data that Gaia will provide, in order to add value to our existing and expanding databases. With reliable parallaxes, and with the ability to measure small astrometric shifts during transits, it will become very much easier to separate dwarfs from giants, and genuine planet candidates from hierarchical triples and other binary impostors. By combining databases in an intelligent way, I am confident that we will be able to reduce the false-positive rate dramatically. This is important, because we still need to at least double the number of ground-based planet discoveries in order to understand the importance of processes like Kozai migration and tidal orbit shrinkage. Our membership of the HARPS-North project will be invaluable for deepening our radial-velocity follow-up searches, and our partnership in the Las Cumbres network will also enable us to perform rapid and efficient photometric follow-up.