Organisation/Company: University of Bristol
Department: School of Physics
Research Field: Astronomy » Astrophysics
Researcher Profile: First Stage Researcher (R1)
Positions: PhD Positions
Country: United Kingdom
Application Deadline: 15 Jan 2025 - 23:59 (Europe/London)
Type of Contract: Temporary
Job Status: Full-time
Hours Per Week: 40
Offer Starting Date: 1 Oct 2025
Is the job funded through the EU Research Framework Programme? Horizon Europe - MSCA
Reference Number: HORIZON-MSCA-2023-DN-01-01
Marie Curie Grant Agreement Number: 101168906
Is the Job related to staff position within a Research Infrastructure? No
Offer Description
The TALES doctorate network in a nutshell
The offered PhD position is part of the TALES (Time-domain Analysis to study the Life-cycle and Evolution of Supermassive black holes) Doctorate Network, a consortium of 10 astrophysics research groups, 8 industrial and 4 academic partners spread across Europe that aims to study the feeding and feedback cycle of supermassive black holes. The TALES doctorate candidates will (i) leverage time-domain astronomy observations from state-of-the-art facilities to map the environment in the close vicinity of supermassive black holes, (ii) use novel analysis methods from the discipline of data science to maximise the information gain from the observations and (iii) develop new theories and models to interpret the data and learn about the physics of the life-cycle of black holes at the centres of galaxies. Parallel to the core research activities above, TALES aspires to implement an ambitious training programme on both technical and complementary skills that is tailored to the needs of the doctorate candidates and includes secondments to industrial and/or academic partners as well as specialised lectures and science communication events.
The Specific Doctoral Project:
It is currently thought that Active Galactic Nuclei (AGN) are powered by accretion of matter onto a supermassive black hole that resides at the centre of almost all galaxies. The accretion disc emission cannot account for the strong X-ray emission detected from these objects. It is thought that there is a “corona” above the disc, in which hot electrons up-scatter optical/UV photons from the disc to X-ray energies. However, the location, size, physical properties, and mechanism that powers the X-ray corona are not currently known.
This PhD project will develop numerical models to describe the X-ray spectra and time variability of accretion discs around supermassive black holes. These models will allow extended corona shapes and velocities, realistic disc geometries, and different spacetimes to be investigated. The energy dependent time lags between the continuum emission from the corona and the reprocessed "reflection" spectrum from the disc will be calculated. The goal is to provide an open-source suite of models that TALES and the wider community can use to fit X-ray time lags, to determine the corona and disc geometries.
More specifically, the project will build on existing software we have developed to model general relativistic effects in the vicinity of a spinning black hole (Gradus.jl). These models will be faster and more flexible than existing models, allowing a range of different accretion disc and corona properties to be investigated. Fitting these models to X-ray data from space-based observatories including XMM-Newton, NuSTAR and XRISM will place important constraints on the nature of the extreme environment of the inner accretion flow. Applying these models to X-ray spectroscopic data, in which emission and absorption features are relativistically smeared (e.g., the iron K alpha fluorescence line and Compton reflection hump), can constrain the black hole spin, inner disc radius, disc thickness, and how centrally concentrated the corona is. These models will also be applied to X-ray timing data, to explain the energy-dependent time delays between variability in the corona and the disc's response. Timing studies can further constrain the corona size, shape, and distance from the black hole. The project will also provide opportunities to model future X-ray observatories such as Athena. Finally, there will be opportunities to explore statistical and numerical techniques to improve the speed and efficiency of fitting complex multi-dimensional models to data.
The doctoral candidate will enrol in the PhD programme of the School of Physics at the University of Bristol where they will be based and supervised by Dr Andy Young. Foreseen secondments include the University of Crete, Athens National Observatory, and industrial partners of the TALES Doctorate Network.
Where to apply
E-mail: Andy.Young@bristol.ac.uk
Requirements
Research Field: Astronomy » Astrophysics
Education Level: Master Degree or equivalent
Skills/Qualifications:
* Master of Sciences in physics or mathematics (to be completed by the start date)
* Proficiency in English, both written and spoken
* Solid computational background
* Strong writing and communication skills compatible with an entry-level research position.
* Ability to work independently and take initiative
* Effective teamwork skills and collaborative mindset
Specific Requirements:
The successful candidate will engage in a rigorous PhD program that involves a demanding travel schedule, including mandatory secondments with both industrial and academic partners. Participation in a variety of training sessions, dissemination activities, and outreach events will also be required. Given the nature of the program, the ability to adapt quickly to new environments and a willingness to travel frequently are essential.
Languages: ENGLISH Level Excellent
Additional Information
The successful candidate will be offered a 36-month full-time employment contract with a very competitive annual salary. Additional allowances may be available based on family circumstances, in accordance with the MSCA provisions.
The recruited researcher will have the opportunity to work within an international and multidisciplinary team that includes 11 doctoral candidates spread in 10 universities across Europe, a total of 14 astrophysics research groups and 8 industrial partners that are active in the fields of data science or education.
As part of the TALES Doctorate Researcher program, the candidate will benefit from a wide range of professional and personal development opportunities through targeted training events. They will acquire a unique skill set that bridges astrophysical modelling, astronomical observations, and data science, positioning them at the forefront of interdisciplinary research in these fields.
Eligibility criteria
The following conditions apply to the offered position:
Applicants must be Doctoral Candidates, i.e., not already in possession of a doctoral degree at the date of the recruitment. Researchers who have successfully defended their doctoral thesis but who have not yet formally been awarded the doctoral degree will not be considered eligible.
Trans-national mobility: The applicant—at the date of recruitment—should not have resided in the country where the research training takes place for more than 12 months in the 3 years immediately prior to recruitment, and not have carried out their main activity (work, studies, etc.) in that country. For refugees under the Geneva Convention (1951 Refugee Convention and the 1967 Protocol), the refugee procedure (i.e. before refugee status is conferred) will not be counted as ‘period of residence/activity in the country of the beneficiary’.
Selection process
Interested applicants are invited to use the University of Bristol online application form, and select “Physics (PhD)” as the programme. At the top of your personal statement, please state clearly that you are applying for a PhD in astrophysics and state that you are interested in the "X-ray reverberation" project and whether you wish to be considered for other projects. A research proposal is not required for an astrophysics application, so please upload a single page pdf with "Research proposal not required" to satisfy the submission tool.
The Doctorate Candidate will work within the Astrophysics Group of the University of Bristol. The group is active in several research areas, specialising in cosmology, the formation of clusters and galaxies, active galaxies, high-energy astrophysical processes, the formation of extrasolar planets, data intensive astronomy, software development, and numerical modelling. Observational work in the group uses large ground-based and satellite telescopes from the radio to the X-ray bands, while our theoretical work is tied closely to the interpretation of these data. We are a friendly and welcoming research group.
Location: HH Wills Physics Laboratory, Tyndall Avenue
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