Dr James Aird and Professor Julian Osborne
Supermassive black holes, with masses up to billions of times the mass of the Sun, are found at the centres of most galaxies, including our own. In some galaxies, these black holes are rapidly growing as matter falls in, heating up and producing huge amounts of electromagnetic radiation, outshining all the stars in the galaxy. As pioneers in the field of X-ray astronomy for over 50 years, University of Leicester researchers have played a lead role in identifying and characterising these central, growing supermassive black holes – known as “active galactic nuclei” or AGN.
But where do supermassive black holes come from? How do the very first black holes form and achieve their extremely large masses? Recent discoveries of extremely bright AGN in the distant Universe (looking back to the first ~1 billion years of cosmic history) indicate that supermassive black holes were already in place at these early times, when the first stars and galaxies were also forming. Determining the mechanisms that form these very first black holes remains a fundamental challenge in astrophysics.
Tracking the formation and growth of the earliest supermassive black holes is one of the main science objectives for the Athena X-ray Observatory – ESA’s next large X-ray mission (due to launch ~2031). Athena will enable new X-ray diagnostics of the Universe thanks to its unprecedented sensitivity and fast survey capabilities. Researchers in Leicester have helped define this next-generation mission, playing a lead role in the design and construction of the spacecraft, development of the ground systems, and science plans.
This PhD offers the opportunity to join the Athena project, working with leading researchers in Leicester and collaborators across Europe. The student will develop new techniques to model the formation of the first supermassive black holes, describe their subsequent growth within the early galaxy population and predict their observational properties. These predictions will be used to perform sophisticated simulations of the Athena survey programme, expected to form ~1 year of the observing time of this flagship mission. The student will also develop new data analysis techniques, placing them at the forefront of the future of X-ray astronomy.
• Starting from existing theoretical models of galaxy populations, develop flexible prescriptions to place black holes within these simulated galaxies and track their growth via periods as AGN.
• Produce mock catalogues, providing realistic predictions of the physical properties of AGN and their host galaxies as well as the observational signatures across the electromagnetic spectrum (spanning optical, infrared and X-ray wavelengths).
• Compare these predictions to data from current X-ray surveys to motivate refinements to our model.
• Use the mock catalogues to perform sophisticated simulations of Athena X-ray surveys as well as the supporting imaging at other wavelengths that will be provided by future space- and ground-based telescopes. Develop techniques to analyse these data and measure the properties of galaxies and black holes.
• Alter the model framework to explore the impact of different supermassive black hole formation mechanisms.
• Help define the requirements for surveys with Athena and other forthcoming astronomical facilities.
- 1. Observational Signatures of High-Redshift Quasars and Local Relics of Black Hole Seeds
Reines & Comastri 2016 https://arxiv.org/abs/1609.03562
2. The Formation and Evolution of Massive Black Holes Volonteri 2012, Review for Science Special Issue https://arxiv.org/abs/1208.1106
3. Cosmic X-ray surveys of distant active galaxies: The demographics, physics, and ecology of growing supermassive black holes Brandt & Alexander 2015, The Astronomy & Astrophysics Review, https://arxiv.org/abs/1501.01982
4. The Hot and Energetic Universe: The formation and growth of the earliest supermassive black holes Aird et al. 2013, https://arxiv.org/abs/1306.2325
5. The Hot and Energetic Universe: A White Paper presenting the science theme motivating the Athena mission Nandra et al. 2013, http://arXiv.org/abs/1306.2307