Resolving How Black Holes Influence Galaxy Evolution

Our Sun is just one of hundreds of billions of stars inside our home galaxy - the Milky Way. By observing the motions of stars located at the centre of our galaxy an amazing discovery was made: there lies an invisible object containing 4 million times more mass than the Sun. This is a supermassive black hole, and in fact all large galaxies contain such an object at their centres. As gas gets close to these supermassive black holes the become incredibly hot and produce vast amounts of energy as light or as "jets" of charged particles. This energy has the potential to heat gas and to blow it away from the host galaxy. This is gas that could otherwise have gone on to form new stars. Therefore, these supermassive black holes theoretically have the incredible potential to dramatically change the future of the galaxies that they reside in. This includes the supermassive black hole at the centre of our own Milky Way. Accepted galaxy formation theories currently state that if this energy injection from their central supermassive black holes did not occur, galaxies would contain more stars and these stars would be packed more closely together. Whilst this is a strong theoretical idea, there is a stark lack of direct observational tests of the different possible physical models of this process. With this fellowship I plan to inform galaxy formation theory by combining exquisite observational data sets with bespoke simulations to resolve the outstanding question of how supermassive black holes influence the life of galaxies.

Exciting new observing facilities, available now and in the near future, promise to give us the data needed to understand the relationship between supermassive black holes and their host galaxies. In this Fellowship, I will be using such world-class facilities, operating across the electromagnetic spectrum. This includes, what will be the world's largest telescope operating at visible-infrared wavelengths, the Extremely Large Telescope, which is being built in Chile by my Project Partners the European Southern Observatory. To understand the galaxy population as a whole, and to search for important underlying trends, I will use spectroscopy from unprecedently large samples of galaxies. I will then use follow-up observations of carefully selected galaxies to measure in meticulous detail the conditions and motions of gas. I will test galaxy formation theory against these observations by producing direct observational predictions from extremely detailed simulations of the gas. I will: (1) establish how common it is for rapidly growing black holes to drive gas out of galaxies; (2) calculate how much energy and mass is being carried by the outflowing gas in different phases (e.g., molecular or ionised gas) and; (3) establish to what extent star formation in the host galaxy is affected by these processes.

I will also use this research to make data more accessible to the blind and vision impaired (BVI) community. This builds on my previous public engagement work and will be in partnership with volunteers from local BVI community groups and the Space Telescope Science Institute in the USA. New methods will be explored to represent data through sound for astronomy research and then wider academic and industrial applications.

This project also invests heavily in training and development of early career researchers (Research Associates and PhD students) and will provide them with skills in Big Data and collaborative coding. It will also promote to the general public the UK's involvement in developing the Extremely Large Telescope. These efforts will demonstrate that astronomy involves a wide range of skilled people including engineers and software developers. This Fellowship will also involve constructing large spectroscopic databases that can be accessed and analysed by astronomers all over the world.