School of Physics & Astronomy

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.

 PhD in Photonics
 PhD in Condensed Matter
 PhD in Astrophysics

Search current PhD opportunities in the School of Physics & Astronomy:-




Astrophysics

Galactic Dark Matter Effects from New Physics of Modified Gravity or Dark Energy
Zhao, Dr Hongsheng - hz4@st-andrews.ac.uk

We explore alternatives to the Cold Dark Matter framework by adding new physics in Dark Matter.
The new physics could include Modified Gravity or matter with fifth force interactions.
Several rare coincidences of scales in standard particle physics
are needed to explain why the negative pressure of the cosmological dark energy (DE)
(i) coincides with the positive pressure of random motion of dark matter (DM) in bright galaxies,
(ii) is within order of magnitude of the energy density of neutrinos, if it is allowed to have a mass of eV.
(iii) why Dark Matter in galaxies seems to follow the Tully-Fisher-Milgrom (MOND) relation of galaxy rotation curves, rather than the CDM predicted profile.
The aim is to link empirical dark matter constraints in galaxies with the cosmology.
The work can be purely theoretical using the Euler-Lagrangian approach. Or empirical by fitting galaxy velocity distributions and Gravitational Lensing data.
A bad case of split personality
Jardine, Prof Moira - mmj@st-andrews.ac.uk

Recent studies of the magnetic fields of very low mass stars shows a strange and so far unexplained behaviour. Some have strong, simple magnetic fields, and some have much weaker, complex, solar-like field magnetic fields. We do not fully understand why this difference occurs, but this project involves using the maps of the magnetic fields of these star to explore the physics of their coronae and winds and to examine the impact on any orbiting planets.
A complete census of rapidly quenching galaxies over cosmic time
Wild, Dr Vivienne - vw8@st-andrews.ac.uk

It has been known since the 1920's that most local galaxies can be morphologically classified as spirals or ellipticals. In the last century advancing galaxy surveys have demonstrated that morphology strongly correlates with many other galaxy physical properties: spiral galaxies are typically forming stars, contain cold gas and dust, live in less dense environments, and have modest-sized central black holes, whereas elliptical galaxies are "quenched" (not forming stars), surrounded by hot gas, live in denser environments, and have larger black holes. Despite precise statistical characterisation of these properties throughout much of cosmic history, the underlying physics that separates galaxies into star forming vs. quenched, with all attendant correlations, remains unclear. Understanding the *pathways* by which galaxies quench is a crucial outstanding question at the heart of modern galaxy formation and evolution, impacting a range of astrophysical studies from star formation and interstellar medium to dark matter and dark energy.

In this project we will combine the analysis of optical/NIR photometry and upcoming spectroscopy from the new MOONS NIR spectrograph on the VLT to identify and characterise the properties of rapidly quenched galaxies from redshifts of 0 to 2 in the real and simulated Universes. We will study their environment and gas properties to identify trends that should be reproducible in advanced cosmological hydrodynamic simulations. Comparison of data and simulations will elucidate the role of rapid quenching in the build up of the red sequence.

This project will work closely with Romeel Dave in Edinburgh (rad@roe.ac.uk), who runs the SIMBA and MUFASA galaxy evolution simulations. Real and mock data is in hand to commence the project. During the lifetime of the project new data will become available from the MIGHTEE survey (HI and radio SFRs) and VLT/MOONS (rest-frame optical spectroscopy of redshift 1-2 galaxies).

This is an exciting time to embark on such a project, with upcoming MOONS data set to revolutionise our understanding of quenching galaxy properties, and simulations such as Simba finally producing galaxies with similar colours to observed rapidly quenched galaxies.

References
========

MOONS: https://www.eso.org/sci/facilities/develop/instruments/MOONS.html
MIGHTEE: https://arxiv.org/abs/1709.01901

http://adsabs.harvard.edu/abs/2018MNRAS.473.1168R
http://adsabs.harvard.edu/abs/2016MNRAS.463..832W
http://adsabs.harvard.edu/abs/2017MNRAS.471.1671D
Angular momentum loss and mass loading of stellar winds - slingshot prominences in action
Jardine, Prof Moira - mmj@st-andrews.ac.uk

Many solar-like stars show cool, dense clouds of gas trapped within the million-degree plasma of their outer atmospheres (or coronae). These so-called ``slingshot prominences'' carry away angular momentum when they are ejected and also are also responsible for mass-loading of the stellar wind. As a result, they may form an important part of the spin-down of young stars, and their impact on orbiting planets may lead to enhanced stripping of the planetary atmosphere.
Annihilation of Dark Matter
Zhao, Dr Hongsheng - hz4@st-andrews.ac.uk

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.
CHAMELEON -- Virtual laboratories for exoplanets and plane-forming disks
Helling, Dr Christiane - ch80@st-andrews.ac.uk
Woitke, Dr Peter - pw31@st-andrews.ac.uk

Retrieving (from data), predicting (from detailed models) and thereby understanding the link between the chemical composition of planet-forming disks and exoplanet atmospheres is a challenging task. In this Marie-Curie Innovative Training Network (MC-ITN), we focus on the development of Virtual Laboratories which will be the crucial tool to analyse in detail current and future disk and exoplanet observations. Virtual laboratories play a key role in simulating yet unexplored physico-chemical environments. In addition, while observational data are often hampered by incompleteness in terms of frequency coverage, time coverage, different instrument systematics when combining data etc., Virtual Laboratories can overcome these shortcomings and are a key pre-requisite to answer the questions whether our Solar System is unique and how life emerged.

The CHAMELEON consortium advertices 15 PhD places throughout Europe:
https://chameleon.wp.st-andrews.ac.uk/recruitment/

ESR 5, 6, 7 and 9 will be in St Andrews.

The CHAMELEON students will be part of the St Andrews Centre for
Exoplanet Science: https://www.st-andrews.ac.uk/exoplanets
Charge conservation and cloud formation in planet atmospheres

As result of formation and evolution processes, exoplanets can have hugely different properties, e.g. giant gas planets, rocky planets, mini-neptunes. Today's best constrained exoplanets are short period, hot Jupiters which show `muted' molecular features, enhanced
Rayleigh scattering slopes in the optical, and dynamic features like onsets in the brightest optical emission of the planet. These features arise from a globally circulating and cloud forming atmosphere (Lee et al. 2016 MNRAS 640) which is driven by an intense irradiation field from the host star. Both, dynamics and radiation ionise cloud particles (Helling et al. 2011, ApJ 737; Rodíguez-Barrera et al. 2018, A&A 618).
In order to understand the myriad of observational data from present (HST, Spitzer) and future space missions (CHEOPS, JWST, Ariel, PLATO), a thorough understanding of the cloud formation processes is required. The key processes to cloud formation, nucleation and surface growth, will be studied under the effect of ionisation. The effect of ionised particles is essential for cloud formation on Earth but little is known for exoplanets.

This project is part of the Marie Sklodowska-Curie Innovative Training Network (ITN) CHAMELEON “Virtual Laboratories for Exoplanets and Planet Forming Disks” (chameleon.wp.st-andrews.ac.uk). The ITN combines the expertise of eight European research institutes (Universities of St Andrews, Groningen, Copenhagen, Edinburgh, Leuven and Antwerp, the Max-Planck Institute in Heidelberg and the Netherlands Institute for Space
Research) to cover all relevant aspects for this complex modelling task, joining the expertise in planetary atmospheres and protoplanetary disks, including observation and interpretation. The network will consist of 15 Early Stage Researchers (PhD students) and the respective supervisors/local research groups. For a complete list of all open PhD positions within this training network please visit http://chameleon.wp.st-andrews.ac.uk/recruitment/.
Determining the origins of galaxy bimodality using hierarchical Bayes methods
Wild, Dr Vivienne - vw8@st-andrews.ac.uk

How galaxies form and evolve is one of the outstanding questions of modern astrophysics. We have known for many decades that massive galaxies come in two main types - elliptical/quiescent and spiral/star-forming. However, it remains largely unknown why some galaxies are still forming stars while others are "red and dead". Extremely large galaxy 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, but significant improvements in methods are required to dramatically improve our understanding of the physics behind the observable properties of galaxies.

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 galaxy spectral energy distributions (SEDs) at all redshifts (Walcher et al. 2011). The result is robust physical properties, such as galaxy stellar mass, dust content and star formation history, together with well quantified degeneracies between these parameters. However, by treating galaxies as independent entities to determine their physical properties, we are missing vital population information. A better approach would be to treat galaxies as a population of objects with a common origin and common underlying variables. This could tighten constraints on the physical properties of individual galaxies as well as the underlying relationships that impact the life of galaxies. It could also allow us to extract information from larger surveys with lower quality observations.

Hierarchical Bayes techniques have been used in the astronomical literature to solve problems as diverse as quasar redshift estimation (Bovy et al. 2011), exo-planet orbit analysis (Hogg et al. 2011), properties of supernovae light curves (Mandel et al. 2009), and photometric redshifts (Leistedt et al. 2016). They differ from standard Bayesian methods by fitting the entire dataset in a coherent manner, instead of single objects as entirely independent entities. By applying these methods to galaxy evolution studies, we will improve our ability to break degeneracies between physical parameters and understand the underlying processes governing galaxy evolution. These methods could be applied to e.g. complete populations of galaxies in spectroscopic or photometric surveys, or entire integral field datacubes of single galaxies.

This interdisciplanary project will be jointly supervised by Drs Vivienne Wild and Michail Papathomas in the Schools of Physics and Astronomy and Mathematics and Statistics respectively. Dr Wild has built her career around developing and applying novel statistical techniques to explore datasets on galaxy evolution, focussing most recently on understanding the nature of post-starburst galaxies. Dr Papathomas is an expert in Bayesian modelling, both in the development of new methods and their application to a wide variety of datasets.

Large extragalactic datasets are already available for analysis, both at low and high redshift. The School of Physics and Astronomy is a member of the UK participation group in SDSS-IV, the fourth generation of Sloan Digital Sky Surveys, a large international collaboration encompassing several astronomical surveys. The methods developed during the project could also be applied to upcoming datasets to which the group has proprietary access such as DESI bright galaxy survey, LSST science verification data and VLT/MOONS near-infrared spectroscopic survey.

The project involves the development of statistical techniques to make them applicable to astronomical datasets. This project would suit students with a background in (astro)physics but strong aptitude for maths and statistics, and students with a background in maths or statistics and interest in astrophysics.

For more information please contact Dr Vivienne Wild and Dr Michail Papathomas (vw8@st-andrews.ac.uk, M.Papathomas@st-andrews.ac.uk).


References:
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
Leistedt B., Mortlock D., Peiris H., 2016, MNRAS, 460, 4258
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

Surveys:
SDSS-IV www.sdss.org
LSST www.lsst.org
DESI www.desi.lbl.gov
MOONS https://vltmoons.org/science-2/

Diffuse ionized gas in galaxies
Wood, Dr Kenny - kw25@st-andrews.ac.uk

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 our newly developed radiation hydrodynamics codes that incorporate feedback processes including photoionisation, stellar outflows, and supernovae. Output from our 3D rad-hydro simulations will be compared with emission line observations of the diffuse ionised gas.
Dissecting galaxies in transition
Wild, Dr Vivienne - vw8@st-andrews.ac.uk

The number density of `red and dead' elliptical galaxies increases with cosmic time, meaning galaxies must be transitioning from star-forming disks. In this project we will use the SDSS-IV MaNGA integral field survey alongside mock observations of hydrodynamic simulations to move beyond demographics and pin down which physical processes are responsible for this transition, as a function of stellar mass and environment.

Massive galaxies in the nearby Universe typically fall into two distinct populations (e.g. Strateva et al. 2001; Baldry et al. 2004): actively star-forming disk galaxies, and `red and dead' elliptical galaxies with little or no signs of ongoing star formation. The bimodality in the star-forming properties of massive galaxies has existed since at least z~2 (Tomczak et al. 2014), and the strong correlation between star-forming properties and morphology holds to a similar epoch.

The increasing number density of red-sequence galaxies with cosmic time at fixed stellar mass (e.g. Moutard et al. 2016) tells us that galaxies move from the blue-cloud to the red-sequence by having their star formation halted (`quenched'). Coincidentally, the typical star formation rate of galaxies decreases as they exhaust their gas supplies, but this process is unable to account for the alteration in the galaxies' morphologies. Many different mechanisms have been proposed to partly or wholly explain the build-up of the quenched elliptical population with time, such as gas stripping, merger induced starbursts, AGN feedback and morphological quenching.

Catching galaxies that are in the act of transition, and studying both their evolving demographics and their properties in detail, alongside mock observations from state-of-the-art simulations, are the ways to make further progress (Wild et al. 2009). These objects are rare, and only recently have surveys been large enough for us to be able to constrain the number density evolution of green-valley and post-starburst galaxies, alongside the quiescent galaxies we expect them to evolve into.

The advent of highly multiplexed integral field surveys, alongside well developed hydrodynamic galaxy simulations, means the time is perfect for a fully encompassing study of all types of candidate-transition galaxies. The fossil record of a galaxy's formation history is encoded in its morphology, stellar kinematics, stellar populations and dust, ionised gas content and kinematics. The MaNGA survey provides access to all of these, alongside robust control samples, volume correctable number densities, a wide range of environments and stellar masses. Importantly, comparison to both idealised and cosmological hydrodynamic simulations is now possible, converted into mock data cubes to be analysed in exactly the same way as the data.

In this project we will perform an integrated analysis of the morphologies, shapes, spatially resolved kinematics and stellar populations of the largest ever sample of local post-starburst, blue-ellipticals, red-spirals and green-valley galaxies observed with an integral field unit, alongside large sets of control samples and hydrodynamic simulations. We will aim to understand what are their ancestors and descendants and thereby understand whether they are truly transitioning populations, and on what timescales. We will use these results to interpret data from high-redshift surveys, where post-starburst galaxies are far more common and potentially important for building the present-day galaxy bimodality (Wild et al. 2016).

Strateva et al. 2001, AJ 122, 1861
Baldry et al. 2004, ApJ 600, 681
Tomczak et al. 2014, ApJ, 783, 85
Moutard et al. 2016, A&A, 590, 103
Wild et al. 2009, MNRAS, 395, 144
Wild et al. 2016, MNRAS, 463, 832
MaNGA survey : http://www.sdss.org/surveys/manga/
Echo Mapping of Black Hole Accretion Flows in Active Galactic Nuclei
Horne, Prof Keith - kdh1@st-andrews.ac.uk

This project qualifies as anSTFC studentship in Data-Intensive Science.

Light travel time delays enable micro-arcsecond mapping of accretion discs and broad emission-line regions around the super-massive black holes in the nuclei of active galaxies. Using our share of time on the LCOGT robotic telescope network, along with data from HST, Swift and Kepler satellites, we are monitoring spectral variations of Active Galactic Nuclei to measure black hole masses, accretion rates, and luminosity distances. By decoding information in the reverberating emission-line profiles, we make 2-dimensional velocity-delay maps of broad emission-line regions, mapping the velocity field and ionisation structure of the accretion flows. The student will acquire and analyse such datasets, fitting parameterised models using MCMC methods, image reconstruction using Horne maximum entropy fitting code MEMEcho, and photo-ionisation codes such as Ferland's Cloudy.
Exoplanet atmospheres: Microphysics of cloud formation

As result of formation and evolution processes, exoplanets can have hugely different properties, e.g. giant gas planets, rocky planets, mini-neptunes and possibly carbon-rich planets. The understanding of these objects is, to a large extent, hampered by clouds obscuring their atmospheres. Clouds play a key role for the atmospheric dynamics and
chemistry, as they are important opacity sources and deplete the local gas phase (Helling 2019, Exoplanet Clouds, Annual Review of Earth and Planetary Sciences 47). In order to understand the myriad of observational data from present (HST, Spitzer) and future space
missions (CHEOPS, JWST, Ariel, PLATO), a thorough understanding of the cloud formation processes is required. The process that kicks off the cloud (or dust particle) formation is the nucleation process by which gas-phase species grow to larger clusters which then grow into condensation seeds. This project aims to conduct theoretical work on the nucleation process that is equally applicable to modelling cloud formation in exoplanets and brown dwarfs, and to dust formation in AGB stars (Decin et al. 2017, A&A 608). We will combine computational
chemistry calculation with physical cloud formation modelling (Helling & Fomins 2017, PhiTransA 371).

The selected PhD students will be offered a fully funded PhD place with a required training secondment for this position foreseen at the University of Leuven, with an additional short training at the University of Copenhagen. The funding will be commensurate to the standard scale for PhD students in according to the Marie-Curie funding rules. The successful PhD applicants will have to register at, and comply with, the regulations of the St Leonard’s Postgraduate College at the University of St Andrews and the Arenberg Doctoral School of
the KU Leuven. The successful PhD applicants will follow a doctoral programme including personal training in management, science communication, and teaching.
Feedback in young stellar clusters
Cyganowski, Dr Claudia - cc243@st-andrews.ac.uk

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
cluster formation.
Feedback processes in star forming regions and the interstellar medium
Wood, Dr Kenny - kw25@st-andrews.ac.uk

This project will use (and futher develop) our new radiation hydrodynamics codes to syudy the effects of stellar feedback on the structure, dynamics, and star formation rates in star forming regions (parsec sizescales) and the interstellar medium (kiloparsec sizescales). Feedback processes that are readily incorporated into our codes include photoionisation, radiation pressure, dust heating, stellar outflows, and supernovae. In addition to studying these processes in star forming regions, the new numerical codes are also applicble to numerical studies of galactic outflows and the impact of feedback processes and leakage of ionising radiation into the intergalactic medium.

Informal enquiries to Kenny Wood: kw25@st-andrews.ac.uk
Grain Charges and Lightning in Protoplanetary Disks
Woitke, Dr Peter - pw31@st-andrews.ac.uk

Project Description:
The thermo-chemical state of circumstellar disks determines the composition of planets that form in them, and is hence the key to understand exoplanet diversity. Yet, the temperature and chemical composition of the gas in these disks is not known, in particular the properties of the gas in the midplane inside of ∼10 au (Woitke et al. 2018, A&A 618, 57), where most of the planets form. In this project, we want to study grain charging processes in protoplanetary disks and their feedback on gas ionisation and observation of line emission by molecular ions. Based on a moment method developed in Thi et al. (2018, arXiv 1811.08663), we want to compute the size-dependent charge distribution function of grains f(a,Z) in the disk, where a is the grain radius and Z its charge, based on our state-of-the-art disk modelling software ProDiMo (Woitke et al. 2016, A&A 586, 103). In particular, we want to include the so-called tribo-electric effect, where grains undergo frictional charging when they collide with each other in a turbulent environment. In combination with dust settling, this effect is known to cause electrification of volcano plumes and, more general, lightning in the Earth atmosphere (Helling et al. 2016, Survey in Geophysics 37, 705). It is hence the aim of this project to find out in how far this mechanism also applies to protoplanetary disks, and could change the chemical composition and ionisation in disks.

Innovative Training Network (ITN):
This project is part of the Marie Sklodowska-Curie Innovative Training Network (ITN) CHAMELEON “Virtual Laboratories for Exoplanets and Planet Forming Disks” (http://chameleon.wp.st-andrews.ac.uk/). The ITN combines the expertise of eight European research institutes (Universities of St Andrews, Groningen, Copenhagen, Edinburgh, Leuven and Antwerp, the Max-Planck Institute in Heidelberg and the Netherlands Institute for Space Research) to cover all relevant aspects for this complex modelling task, joining the expertise in planetary atmospheres and protoplanetary disks, including observation and interpretation. The PhD position is fully funded for a period of 3.5 years. All students will obtain double degrees. Training secondment for this position is foreseen for six months at the Niels-Bohr Institute in Copenhagen, under the supervision of Prof. Uffe G. Jørgensen, see www.astro.ku.dk/~uffegj. As Marie Sklodowska-Curie fellows, you will receive generous benefits, including a fixed salary with additional mobility and family allowances. The network will consist of 15 Early Stage Researchers (PhD students) and the respective supervisors/local research groups. For a complete list of all open PhD positions within this training network, including those of our European partners, please see http://chameleon.wp.st-andrews.ac.uk/recruitment/.

Requirements:
We seek an excellent student with a strong background in physics or astrophysics. Successful candidates must hold a Masters degree or equivalent by the starting date of the position. Previous research experience on planet forming disks and/or astrochemistry, and a track record of team work/mobility will be important criteria for the selection. This is a computational project: some prior knowledge of coding would be useful (e.g., Python and Fortran). Note that the general eligibility and mobility rules of Marie Sklodowka-Curie Actions apply, i.e. applicants must not have resided or carried out their main activity (work, studies, etc.) in the country of the main host institution (in this case the UK) for more than 12 months in the 3 years immediately before the recruitment date. If you have been residing in the UK, please consider to apply to the open positions of our European partners (http://chameleon.wp.st-andrews.ac.uk/recruitment/).

Application documents
Your application package should contain (i) a CV including publication list if applicable, (ii) a statement of interest (max. one page, including a brief description of research interests and relevant experience), (iii) copies of university grades, certificates and/or diplomas, (iv) two letters of reference to be sent by the application deadline, (v) a statement that confirms that you undestood the requirements of the joint degree and the Marie Sklodowska-Curie mobility criteria as outlined at https://chameleon.wp.st-andrews.ac.uk/recruitment/. Use the portal of the School of Physics & Astronomy in St Andrews University https://www.st-andrews.ac.uk/physics/prosp_pg/phd/index.php to upload your application documents. The application deadline is 06/01/2020, however, applications that arrive after this date may also be considered until all ITN positions are filled. The foreseen start date is September 2020.
Machine Learning from Complex Disk Models
Woitke, Dr Peter - pw31@st-andrews.ac.uk

Project Description:
Molecular emission features observed in the near and mid infrared, for example with the VLT and JWST, will allow us to determine the chemical composition of the gas in protoplanetary disks in the planet-forming regions within 10 au around new-borne stars. This project will combine our previous expertise in modelling the line radiative transfer, chemistry and heating/cooling balance in disks, see Woitke et al. (2016, A&A 586, 103) with new machine learning techniques developed in the exoplanet community, e.g. Zingales & Waldmann (2018, AJ 156, 268). Neutral networks (NNs) will be trained on the predictions by tens of thousands of complex thermo-chemical 2D disk models, where we will apply the radiative transfer code FLiTs (Woitke et al. 2018, A&A 618, 57) to post-process the ProDiMo results to identify the spectral signatures. Using an algorithm developed for the ARCiS code (artful modelling of cloudy exoplanet atmospheres, author M. Min), these NNs will enable us to retrieve the chemical composition and the physical disk parameters, including their errorbars, from the observations. We can then use these new machine learning algorithms to quickly predict the emergent near-mid infrared line emission spectra from disks as function of physical parameters like UV irradiation, dust/gas ratio and element abundances, capable to thoroughly fit and analyze JWST data to determine the physical disk parameters and their observational uncertainties, taking into account all degeneracies.

Innovative Training Network (ITN):
This project is part of the Marie Sklodowska-Curie Innovative Training Network (ITN) CHAMELEON “Virtual Laboratories for Exoplanets and Planet Forming Disks” (http://chameleon.wp.st-andrews.ac.uk/). The ITN combines the expertise of eight European research institutes (Universities of St Andrews, Groningen, Copenhagen, Edinburgh, Leuven and Antwerp, the Max-Planck Institute in Heidelberg and the Netherlands Institute for Space Research) to cover all relevant aspects for this complex modelling task, joining the expertise in planetary atmospheres and protoplanetary disks, including observation and interpretation. The PhD position is fully funded for a period of 3.5 years. All students will obtain double degrees. Training secondment for this position is foreseen for 12 months at SRON in Utrecht, The Netherlands, working with Dr. Michiel Min. In addition, regular research visits of the research group of Prof. Inga Kamp are planned at the Kapteyn Institute in Groningen, The Netherlands. As Marie Sklodowska-Curie fellows, you will receive generous benefits, including a fixed salary with additional mobility and family allowances. The network will consist of 15 Early Stage Researchers (PhD students) and the respective supervisors/local research groups. For a complete list of all open PhD positions within this training network, including those of our European partners, please see http://chameleon.wp.st-andrews.ac.uk/recruitment/.

Requirements:
We seek an excellent student with a strong background in physics or astrophysics. Successful candidates must hold a Masters degree or equivalent by the starting date of the position. Previous research experience on machine learning, astrochemistry and/or radiative transfer, and a track record of team work/mobility will be important criteria for the selection. This is a computational project: some prior knowledge of coding would be useful (e.g. Python and Fortran). Note that the general eligibility and mobility rules of Marie Sklodowka-Curie Actions apply, i.e. applicants must not have resided or carried out their main activity (work, studies, etc.) in the country of the main host institution (in this case the UK) for more than 12 months in the 3 years immediately before the recruitment date. If you have been residing in the UK, please consider to apply to the open positions of our European partners (http://chameleon.wp.st-andrews.ac.uk/recruitment/).

Application documents:
Your application package should contain (i) a CV including publication list if applicable, (ii) a statement of interest (max. one page, including a brief description of research interests and relevant experience), (iii) copies of university grades, certificates and/or diplomas, (iv) two letters of reference to be sent by the application deadline, (v) a statement that confirms that you undestood the requirements of the joint degree and the Marie Sklodowska-Curie mobility criteria as outlined at https://chameleon.wp.st-andrews.ac.uk/recruitment/. Use the portal of the School of Physics & Astronomy in St Andrews University https://www.st-andrews.ac.uk/physics/prosp_pg/phd/index.php to upload your application documents. The application deadline is 06/01/2020, however, applications that arrive after this date may also be considered until all ITN positions are filled. The foreseen start date is September 2020.
Mass Distribution of the Galaxy
Zhao, Dr Hongsheng - hz4@st-andrews.ac.uk

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.
New physics for Dark Matter via Modified Gravity/Dark Energy

We explore alternatives to the Cold Dark Matter framework by adding new physics in Dark Matter.
The new physics could include Modified Gravity or matter with fifth force interactions.
Several rare coincidences of scales in standard particle physics
are needed to explain why the negative pressure of the cosmological dark energy (DE)
(i) coincides with the positive pressure of random motion of dark matter (DM) in bright galaxies,
(ii) is within order of magnitude of the energy density of neutrinos, if it is allowed to have a mass of eV.
(iii) why Dark Matter in galaxies seems to follow the Tully-Fisher-Milgrom (MOND) relation of galaxy rotation curves, rather than the CDM predicted profile.

The work can be purely theoretical using the Euler-Lagrangian approach. Or empirical by fitting galaxy velocity distributions and Gravitational Lensing data.
New Physics for Galactic Dark Matter via Modified Gravity/Dark Energy

We explore alternatives to the Cold Dark Matter framework by adding new physics in Dark Matter.
The new physics could include Modified Gravity or matter with fifth force interactions.
Several rare coincidences of scales in standard particle physics
are needed to explain why the negative pressure of the cosmological dark energy (DE)
(i) coincides with the positive pressure of random motion of dark matter (DM) in bright galaxies,
(ii) is within order of magnitude of the energy density of neutrinos, if it is allowed to have a mass of eV.
(iii) why Dark Matter in galaxies seems to follow the Tully-Fisher-Milgrom (MOND) relation of galaxy rotation curves, rather than the CDM predicted profile.

The work can be purely theoretical using the Euler-Lagrangian approach. Or empirical by fitting galaxy velocity distributions and Gravitational Lensing data.
Observations and simulations of massive star formation
Cyganowski, Dr Claudia - cc243@st-andrews.ac.uk
Wood, Dr Kenny - kw25@st-andrews.ac.uk

While the details of the formation mechanism of massive stars remains uncertain, many of the proposed scenarios ultimately rely on accretion via a rotationally supported circumstellar disk or torus. The circumstellar environment of a massive star is subject to feedback processes including photoionisation, radiation pressure on dust, jets and outflows. These feedback effects leave their imprint on the observed images, spectra, and velocity distributions of the circumstellar environment, thus providing further clues to the formation mechanisms in different environments for stars of different masses. This project will combine new high spatial and spectral resolution observations of massive star forming regions together with radiation transfer and radiation hydrodynamics simulations to model the data in order to build up a detailed picture of the environment and conditions leading to massive star formation.
Star formation in dwarf galaxies
Bonnell, Prof Ian - iab1@st-andrews.ac.uk

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.
Star-Planet Interaction
Jardine, Prof Moira - mmj@st-andrews.ac.uk

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 gas content of the cosmic web
Tojeiro, Dr Rita - rmftr@st-andrews.ac.uk

Galaxies have a complex relationship with surrounding gas. Cosmic-web filaments take on especially important roles for halo and galaxy growth: simulations indicate that around 40 percent of the Dark Matter in the Universe is found within filaments, and they act as conduits that feed Dark Matter and neutral, cold gas into halos and galaxies. The neutral cold gas, once accreted onto a galaxy, will almost always form stars, at which point it becomes easily detectable via starlight. However, although a key player in the formation and growth of galaxies, we know astoundingly little about the gas component of the cosmic web, before it reaches the vicinity of a galaxy.

In this project, you will cross-correlate excess absorption in the spectra of distant quasars with filaments detected via the positions of galaxies, to understand the gas content of the cosmic web, far from the influence of dark matter halos. You will work with eBOSS and DESI data, which together provide the densest sample of lines of sight that pierce the low-redshift cosmic web. Your observational work will be complemented by work in cosmological hydrodynamical simulations
The host galaxies of luminous AGN
Wild, Dr Vivienne - vw8@st-andrews.ac.uk

Understanding the link between active galactic nuclei and their host galaxies has become one of the most pressing problems in extragalactic astronomy. What is the impact of the energy released by the AGN on the host galaxy? There is lots of circumstantial evidence that the impact should be substantial, but direct observational evidence is scarce.

One of the key problems is that luminous AGN easily outshine their host galaxies, making it difficult to ascertain what the galaxy properties are. Much work has been done on trying to reveal their morphology (for example, are they merger remnants?), but there have been limited attempts to understand their stellar populations. Stellar populations are key to uncovering their recent history to reveal whether they have recently suffered a sharp decrease in star formation, which would indicate a significant AGN feedback effect.

In collaboration with Prof. Paul Hewett (IoA Cambridge) and Dr Carolin Villforth (Bath) we have recently developed a novel method to decompose AGN spectra into their broad line AGN and host galaxy components. This PhD project will exploit those methods to reveal the stellar populations of QSO hosts as a function of luminosity, eddington ratio and presence/absence of QSO outflow signatures, comparing to control samples to understand the impact of the QSO on the host galaxy.
Triggering of star formation
Bonnell, Prof Ian - iab1@st-andrews.ac.uk

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.
Unveiling the role of environment on the growth of galaxies and dark-matter halos
Tojeiro, Dr Rita - rmftr@st-andrews.ac.uk

One of the challenges in galaxy evolution is to understand the evolutionary paths of different types of galaxies. Although stellar mass (observationally) and halo mass (in simulations) display a dominant role in the formation and evolution of galaxies, the role of environment is less well-understood. This is largely due to the difficulty in defining "environment", and in estimating it from observations.

This project will combine data from three datasets to investigate the role of environment in the local Universe with unprecedented clarity. Local environment will be estimated with the forthcoming DESI survey (currently commissioning - Nov 2019). DESI will observe a high-density, high-completeness sample of galaxies out to z=0.4 over 14,000 sq degrees, starting in 2020. By combining this exquisite dataset with integral field spectroscopy from the MaNGA survey, and deep imaging for the Legacy imaging surveys, you will investigate the role of environment for a variety of physical estimators (such as overdensity over a variety of scales, satellite/central classification, cosmic web estimators and projected correlation function) on integrated and resolved properties of galaxies. Supplementing your observational work with cosmological hydrodynamical simulations, you will understand the implications of your results for the evolution of halos, galaxies and the galaxy-halo connection.