Armagh Observatory is known world-over as a leader in the field of astronomical research; we welcome PhD Candidates every year. Applications for positions starting in Oct 2024 are now open.
Current Research Projects
Magnetic Fields of Degenerate Stars - Supervisor: Stefano Bagnulo
White dwarfs (WDs) are the end point of 90% of stellar evolution. 15–20% of such stars possess strong magnetic fields. The fields range over five dex in strength, from below ten kG (one Tesla) up to about 1000 MG. The fields are roughly dipolar, and show no evidence of rapid secular changes. They seem to be “fossil fields”, produced in earlier evolution that evolve slowly by ohmic decay. At present, there is no single firmly established theoretical scenario that explains how prior evolution through the red giant and AGB phases can leave strong surface fossil magnetic fields in a significant fraction of WDs. Possibilities include retaining fields from earlier evolutionary phases, or field generation during binary mergers.
Using various facilities at the Very Large Telescope, at the Canada-France-Hawaii Telescope, and at the William Heschel Telescope, Armagh astronomers are performing a large survey of magnetic WDs in the vicinity of our solar system, with the goal to understand if and how magnetic fields evolve with time, and if they are correlated to other features of the stellar atmospheric chemistry, mass, and age. A PhD project is offered to help to obtain observational constraints that will be used to understand the origin of magnetic fields in WDs.
The student will learn how to use spectro-polarimetric techniques to detected and model stellar magnetic fields. She or he will help with the preparation of proposal for telescope time, with the execution and analysis of the observations, with the search for correlation between magnetic fields and other stellar parameters, and with the modelling of time series of polarised spectra and of surface magnetic field structure of of WDs. The project will be more theoretically or observationally oriented according to the preference and skills of the student.
For further information contact stefano.bagnulo@armagh.ac.uk
Time Domain Astrophysics - Supervisor: Gavin Ramsay
Time Domain Astrophysics is the branch of astronomy which utilises the apparent brightness variations of objects on timescales ranging from
less than a second (neutron stars) to minutes (compact binary star systems and pulsating stars) to hours (accreting objects) and months
or years (active galactic nuclei and accreting objects) to probe different physical processes. Other examples include supernovae and
exoplanets orbiting other stars.
Armagh is a founder member of the Gravitational-wave Optical Transient Observer (GOTO) project which has robotic telescopes on La Palma in
the Canary islands and Siding Spring in Australia. The prime goal of this project is to detect the optical counterpart of Gravitational
Wave events detected by Ligo/Virgo/Kagara. These telescopes have sufficiently wide sky coverage that we map the entire visible sky every few days. Armagh is also a member of the BlackGem project which currently has three telescopes in Chile and has the same primary goal as GOTO.
The exact project which any a new PhD student would undertake be open according to their interests and expertise. However, it would be
expected to make use of GOTO and BlackGem data, with additional data potentially coming from the TESS satellite and radio data obtained
from I-LOFAR.
For further information contact gavin.ramsay@armagh.ac.uk
Spectroscopy of The Heaviest Stars - Supervisor: Jorick Vink
Some few hundred million years after the Big Bang the Universe lit-up by the formation of the First Stars, which are thought to have been very massive owing to their pristine chemistry. Despite their key role in setting the stage for the subsequent Cosmic chemistry, we know surprisingly little about the properties of the first few stellar generations.
The goal of this observational/modelling Project is to utilize ongoing and new large-scale spectroscopic surveys (HST ULLYSES, X-Shooting ULLYSES at ESO’s VLT in Chile, and WEAVE on the island of La Palma) to determine the fundamental stellar properties, constrain the evolution of massive stars, and assess the final mass before collapsing into a Black Hole.
The project can be be more observational or theoretical depending on the interests and skills of the student.
For further information contact jorick.vink@armagh.ac.uk
The heaviest stars and black holes - Supervisor: Jorick Vink
Some few hundred million years after the Big Bang the Universe lit-up by the formation of the First Stars, which are thought to
have been very massive owing to their pristine chemistry. Despite their key role in setting the stage for the subsequent Cosmic chemistry, we know surprisingly little about the evolution & fate of the first few stellar generations.
The goal of this computational PhD project is to predict the amount of mass the first stellar generations loose through stellar winds, and to
determine the final masses of these stars as Black Holes.
The predicted black hole masses will be compared to data from gravitational wave observatories.
For further information contact jorick.vink@armagh.ac.uk
Developing deep all-sky imaging polarimetry with the VST - Supervisor: Stefano Bagnulo
The VLT Survey Telescope (VST), located in Cerro Paranal (Chile), is a 2.6m telescope with a 268-megapixel camera, called OmegaCAM. It will be equipped with polarimetric optics, then re-commissioned, and will produce the first science data whithin the next three years. At this point, the VST will become the only facility in the world capable of deep imaging polarimetry (thanks to its 2.6m mirror) over a field of view as large as 1 deg x 1 deg. AOP is offering a studentship to help to learn how to make the best use of the telescope in polarimetric mode. The PhD student will help to develop and test calibration and data-analysis procedures, and will have an important role in the identification of the observational projects that can maximise the scientific return of this unique facility. Scientific targets will include solar system objects, interstellar medium, and magnetic stars, and any target for which the rapid follow-up capabilities of the telescope may show of crucial importance. In preparation of the science validation of the VST, the student will also use polarimetric data obtained from ESO instruments and telescopes, in particular the FORS instrument of the Very Large Telescope. The student will be supervised at the Armagh Observatory by Dr Stefano Bagnulo in close collaboration with other international teams, mainly in the Netherlands and in Italy.
For further information contact stefano.bagnulo@armagh.ac.uk