Dr S Nayakshin, Dr R Alexander
No more applications being accepted
Competition Funded PhD Project (Students Worldwide)
About the Project
In the first decade of the century, observations firmly established existence of a supermassive black hole called Sgr A* residing in the very heart of the Milky Way. Sgr A* is also the most massive and important member of the Galaxy as the structure of the Galaxy has been strongly influenced by its violent outbursts in the past. Observations of Sgr A* in the last couple years shed important detail on the last such outburst, enabling us to witness what cannot be observed for any other supermassive black hole. As of a year ago, a revolutionary interferometer called GRAVITY became operational and already provided astonishing results [reference 1] that will enable us to test Einstein’s theory of gravity in the strong field regime and to understand how supermassive black holes work in greater detail.
The Theoretical Astrophysics Group in the University of Leicester has been at the forefront of this -research for well over a decade, providing theoretical support to observers, and helping to lay foundations for some of the most exciting results in the field. Recent observational data provide us with additional physical constraints to explore a range of phenomena occurring in the immediate vicinity of Sgr A* and yet affect the whole Galaxy. In particular, we plan to address:
• Enigmatic X-ray and near infra-red flares (cf. Figure). We proposed in 2012 that such flares are driven by large asteroids being tidally disupted and burnt in the hot atmosphere of Sgr A*, somewhat how this happens for asteroids striking the Sun and Jupiter. This model remains popular in the community and can now be tested in greater detail due to GRAVITY observations [1]. Understanding the flares will improve our understanding of what is in the immediate vicinity of the black hole, and constrain how it grows at the current time.
• Fermi Gamma-Ray telescope discovered in 2010 two Galaxy-wide lobes filled with cosmic rays and very hot gas. We proposed the currently leading scenario [2] which ties these lobes to the outburst of star formation in the central parsec and the simultaneous activity of Sgr A*. Observations recently strengthened the case for this picture. We now have information on Fermi bubble expansion velocities along multiple lines of sights, and additional shocked gas features discovered at high latitudes above the Galactic plane. There is also more information on the density and velocity structure of the Central Molecular Zone in the innermost 100 parsec of the Galaxy. Using these constraints in connection with detailed numerical modelling, we shall improve on our model of how Sgr A* grew about 5 Million years ago and how it launched the outflow reverberating through the Galaxy now.
• New observations from 2017 may hint that the closest vicinity of Sgr A* hosted an enigmatic “quasi-star” object (reference 3). These objects are super-massive blackholes shrouded from view by very massive gas envelopes, somewhat similar to, but scaled-up, versions of massive stars before they explode as supernovae. This hypothesis may help explain the origin of the otherwise puzzling population of the closest young stars. We also suggested that an explosion of the quasi-star might have been more efficient in affecting the innermost Galaxy than the usually considered steady outflow. By comparing our simulations with observations we hope to shed light on this explosive mode of super massive black hole feedback on their host galaxies.
Entry requirements
Applicants are required to hold/or expect to obtain a UK Bachelor Degree 2:1 or better in a relevant subject. The University of Leicester English language requirements apply where applicable.
How to apply
The online application and supporting documents are due by Monday 21st January 2019.
Any applications submitted after the deadline will not be accepted for the studentship scheme.
References should arrive no later than Monday 28th January 2019.
Applicants are advised to apply well in advance of the deadline, so that we can let you know if anything is missing from your application.
Required Materials:
1. Online application form
2. Two academic references
3. Transcripts
4. Degree certificate/s (if awarded)
5. Curriculum Vitae
6. CSE Studentship Form
7. English language qualification
Applications which are not complete by the deadline will not be considered for the studentship scheme. It is the responsibility of the applicant to ensure the application form and documents are received by the relevant deadlines.
All applications must be submitted online, along with the supporting documents as per the instructions on the website.
Please ensure that all email addresses, for yourself and your referees, are correct on the application form.
Project / Funding Enquiries
Application enquiries to [Email Address Removed]
Closing date for applications – 21st January 2019
Funding Notes
This research project is one of a number of projects in the College of Science and Engineering. It is in competition for funding with one or more of these projects. Usually the project that receives the best applicant will be awarded the funding.
Home/EU Applicants:
This project is eligible for a fully funded College of Science and Engineering studentship that includes:
• A full UK/EU fee waiver for 3.5 years
• An annual tax free stipend of £14,777 (2018/19)
• Research Training Support Grant (RTSG)
International Applicants:
This project is eligible for a College of Science and Engineering studentship that includes:
• A full international fee waiver for 3.5 years
• Research Training Support Grant (RTSG)
International candidates must be able to fund their living costs for the duration of the studentship.
References
1. “Detection of orbital motion near the last stable circular orbit of massive black hole Sgr A*”. Gravity collaboration, 2018, Astronomy and Astrophysics, 618, L10. https://arxiv.org/abs/1810.12641
2. “Fermi Bubbles in the Milky Way”, Zubovas, K, Nayakshin, S., 2012, Monthly Notices of the Royal Astronomical Society, 424, 666. http://adsabs.harvard.edu/abs/2012MNRAS.424..666Z
3. “Sgr A* envelope explosion and the young stars in the centre of the Milky Way”, Nayakshin, S., Zubovas, K., 2018, Montly Notices of the Royal Astronomical Society Letters, 478, 127. http://adsabs.harvard.edu/abs/2018MNRAS.478L.127N