Resolving the physics of galaxy formation

Galaxy formation is one of the most fascinating yet challenging fields of astrophysics. The desire to understand galaxy formation has led to the design of ever more sophisticated telescopes and satellites. These observational probes have shown that there is a bewildering variety of galaxies assembling in the early Universe all the way to the present day. The increasing precision and statistical power of existing and upcoming observational data on galaxies may well challenge the standard cold dark matter paradigm for cosmic structure formation, and perhaps even signal the need for additional, new physics. However, the degree to which an interpretation of this wealth of data can succeed depends critically on having accurate and realistic theoretical models of galaxy formation.

Cosmological simulations of galaxy formation provide the most powerful technique for calculating the non-linear evolution of cosmic structure formation. In principle, such simulations can predict galaxy formation in an ab initio manner. However, the enormous dynamic range and the many poorly understood aspects of baryonic processes in galaxy formation introduce significant uncertainties in the results of present simulations, making galaxy formation an unsolved theoretical challenge.

The objective of this proposal is to develop novel theoretical tools to study galaxy formation with an unprecedented level of realism making use of the novel hydrodynamical code AREPO, which has significant advantages in terms of the accuracy of the hydro solver and of the dynamical range which can be achieved by targeted space refinements. The underlying idea is to bridge the gap which currently exists in the modeling of the physical processes occurring at very small scales, e.g. in the star forming regions, and the ones which shape the large scale structure in the Universe. This will be accomplished in two ways: by performing a suit of nested cosmological simulations which will span a much larger dynamical range than has been currently achieved; and by replacing the commonly adopted sub-grid models with detailed descriptions of the interstellar medium and of the accretion flows around black holes. With this strategy it will be possible to address directly which processes are responsible for the structural properties and morphological transformation of galaxies across cosmic time.

The University of Cambridge has one of the most successful programmes for encouraging knowledge transfer and resulting societal impact between University departments and industry both in the UK and elsewhere. Postdoctoral staff employed on the grant have access to and are encouraged to undertake a full range of career development courses, organised by the University, which aid them in identifying and better transferring their applicable skills more widely. These skills include advanced statistical, computational and modelling techniques, systems design, image analysis, data handling, communication of science. The IoA's approach to the search for impact opportunities has been guided by the mechanisms the University has in place to facilitate this. Specifically, it is now involved in the transfer of a range of techniques directly or indirectly developed to support its research. The further research breakthroughs expected though the activities supported by this grant over the period 2013-2016 will in turn drive the development of techniques and processes of wider applicability. For instance the Planck research [3.1] involves the development of advanced modelling techniques which are now actively being applied to development of optics through a small spin out enterprise. Visualisation techniques developed to support the analysis of X-ray data [3.8] have led to the development and open source release to the wider community of a fully featured interactive plotting package. The cutting edge IoA research themes help to inform and set vigorous demands on the processing and image analysis software developed more widely in the ioA, for instance in the IoA's Cambridge Astronomical Survey Unit. These analysis techniques in turn, have been found to be extremely powerful when utilised in other settings, for instance image analysis and data handling systems applied to the medical domain. Thus CASU recently had a one year Knowledge Exchange MRC grant to apply these techniques to the analysis of tissue micro array (TMA) data supporting oncological research programmes at Cancer Research UK's, Cambridge Research Institute (CRI). This work attracting considerable external attention (e.g. The PathGrid system formed the centrepiece of an extended xsnews feature in the Science special issue 'Dealing with Data' (vol 331, Feb 12, 2011).). Published results demonstrate the effectiveness of the analysis applied to the measurement of ER protein expression in TMA data. With co-workers in the CR-UK, The University of Cambridge Dept of Oncology, Strangeways Laboratory, and the Department of Histopathology at Addenbrooke's Hospital in Cambridge, the latest application of PathGrid is to a significant large scale study - with a dataset of over 2400 tumours. Future beneficiaries include BBSRC's Institute of Food Health. CASU are initiating validation pilots with the Dept of Pathology at Addenbrooke's NHS hospital, aiming to deploy the PathGrid processing system in the Addenbrooke's clinical setting of high throughput analysis of routine breast cancer pathology tests. PathGrid has the potential to increase the effectiveness of clinical health care and enhance the quality of life of those with cancer, through improved outcomes through better targeted therapeutic treatments.The IoA has a powerful 'understanding of science' programme. The outreach programme engages teachers, who in turn input IoA research ideas into their primary and secondary school curricula. It highlights women in science, providing role models to inspire future researchers The public observing programme reaches many thousands of people, inspiring them to make their own discoveries of the night sky. The IoA 'Artist in Residence' generates powerful multi-media material placing astrophysical science in the wider cultural context. Taken together IoA science, through its outreach, directly impacts in an uptake of young people entering science and public interest in science.