Astrophysics at the University of Birmingham: Consolidated Grant 2016-2019

Most of our knowledge about the Universe at large has been derived from what scientists refer to as "electromagnetic radiation", ranging from radio waves through infrared radiation and light, to X-rays and gamma rays. This is about to change, since we are on the brink of the first detection of the ripples in space-time known as gravitational waves, which are predicted by Einstein's theory of General Relativity. The Birmingham Astrophysics and Space Research Group is playing a key role in these developments, and is preparing to use the signals from merging black holes and neutron stars to learn more about the evolution of stars, black holes and to test our understanding of gravity itself. We are also developing the advanced technology which will be required to make future improvements in detecting gravitational waves, so that much weaker signals can be studied.

The capabilities of more conventional instruments to probe the distant Universe and cosmic structures at different scales, galaxies and galaxy clusters, continue to improve. We will use some of the most exquisite observations to advance our understanding of how galaxies and clusters form and evolve through cosmic time. A hot topic in astrophysics is the effort to understand the mysterious "dark energy" which powers the accelerating expansion of the Universe. We plan to use clusters of galaxies as probes of the structure and expansion history of the Universe on the largest scales, to advance our understanding of the nature of dark energy.

A few thousand exoplanets have been discovered in our solar neighbourhood. Understanding the properties of these systems, how the formed and how they can survive is of crucial importance to determine what kind of planets exists outside our Solar System, and, ultimately, determine where life could develop. We will use sophisticated computer simulations to explore the characteristics of different populations of these systems, and to infer the presence of (presently) unobserved companions in the data that have been gathered so far.

Within galaxies, the most massive stars have a major impact due to the very high power they radiate, and due to their powerful stellar winds. The magnetic field in these stars plays a major role, and it is surprisingly difficult to estimate how much matter is streaming away from such stars in a wind. We plan to combine computer modelling with observations at different wavelengths to improve our understanding of just how big an impact the magnetic field has on massive stars, their winds and the effects on their surroundings.

In terms of academic impact, the immediate beneficiaries include the UK astronomy community, extending beyond the applicant group. In the longer term, this research will provide new insights into the formation and evolution of galaxies and clusters, lay the foundations for reliable measurements of the mysterious component of our Universe that we call "dark energy", using clusters of galaxies, provide new insights into massive stars and populations of exoplanets, and lead to the opening of a new observational window on the universe through gravitational radiation. Research on gravitational waves is expected to radically alter our understanding of the Universe, including information on the nature of neutron stars and black holes; in the long-term it will offer a new window on the very early Universe, when it is was a fraction of a second old. This will benefit the widest international astronomy/astrophysics community.

With regard to societal impact, cosmology, astrophysics and exoplanets are exciting areas and reliably excellent topics for public outreach. The direct detection of gravitational waves, which is expected towards the end of this grant period, will have a considerable impact. A flourishing of new science activities will inevitably result. An improved understanding of cosmology, clusters of galaxies, amongst the largest structures in the cosmos, planetary systems outside the solar systems, and the astrophysics of compact objects, the cosmic engines behind some of the most impressive and violent events in the universe, will surely catch the public imagination, and produce demand for creative works. Our public engagement activities have already generated new online media for education and outreach, such as interactive computer games. They have attracted considerable attention and as we are developing these games for tablets and other platforms we can expect to reach an even larger audience.

Work that we have carried out in the experimental area has already provided direct benefit to UK industry. Earlier work that we have carried out for the construction of elements of subsystems of Advanced LIGO has already benefited the UK industry with contracts for about £1M. Moreover, we have developed a simple and compact interferometer, which has produced two patents, and now a commercialised version of this device exists. Our programme on interferometry and sensors has already had applications in the development of a new gravity-gradient sensor for use in engineering, underground explorations and archeology. We will also be producing simulation software packages that have wider use in industry, for example for integrated system models of navigation systems.

Of course, the training which post-doctoral research assistants and PhD students receive within our grant-funded programme is also of much wider benefit to the academic and non-academic communities.