Sgr A*, our Galaxy's supermassive black hole

Lead Research Organisation: University of Leicester
Department Name: Physics and Astronomy

Abstract

Studies of Supermassive Black Holes (BH) remain at the forefront of contemporary astrophysics. BHs are synonymous with extreme gravity and physical phenomena. Their astrophysical importance lies in the fact that BHs release vast amounts of energy when they grow, strongly affecting their host galaxies. However, how these processes operate in detail is not understood. Except for one example, observations do not yet resolve the small scales on which BHs devour its food; we also lack causality information between BH outbursts and what they do to the galaxies, and how. Sgr A*, the 4 Million Solar mass BH in the centre of the Milky Way, is the unique exception. It is the closest to us laboratory of BH physics. Although presently very dim, Sgr A* went through a spectacular activity episode ~ 6 Million years ago when a massive gas cloud fell onto it. The resulting BH growth launched powerful outflows that shocked the inner Galaxy's disc, and inflated two Galaxy-scale gamma-ray emitting lobes perpendicular to the disc. In parallel to this, hundreds of young massive stars formed on surprisingly small orbits, whizzing about Sgr A* at speeds approaching a few percent of speed of light.
Our group has led the way in theoretical and numerical simulations studies of Sgr A* activity, providing support to the group of 2020 Nobel prize winner R. Genzel in their work on young stars orbiting Sgr A*. During the last decade observers added one important detail to another on this unique example of BH activity. In this project we shall perform numerical simulations of Sgr A* growth and feedback. By comparing simulation results to a multitude of observational constraints we will create the most detailed yet picture of what happened in the immediate environment of our BH, and how its activity continues to reverberate through the Galaxy.

The end goal of our project is to create a detailed model of Sgr A* recent (in Galaxy's terms) growth, activity, and how it affected the Galaxy on scales from a milli-parsec to many kilo-parsecs. In addition, utilising the unique quality of data for the BH in the Milky Way, we shall investigate a number of so far untested theoretical models for BH growth and feedback in external galaxies. A strong candidate for this project will be interested in theoretical astrophysics and numerical simulations. No prior high performance computing experience is expected. Both public available and in house created software will be provided.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/W507611/1 30/09/2021 29/09/2025
2604619 Studentship ST/W507611/1 26/09/2021 30/03/2025 Aleksandra Calovic