Cosmology and Astrophysics at Portsmouth

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This consolidated grant is to support cosmologists and astrophysicists in the Institute of Cosmology and Gravitation (ICG) at the University of Portsmouth. The ICG was formed in 2002 through a strategic investment from the university, and now hosts 50 researchers making it one of the largest extragalactic astronomy groups in the UK e.g. ranked 8th in research outputs in the recent REF2014.Cosmology and astrophysics are experiencing a golden age of discovery driven by new experiments and theoretical advances. However, we still face three fundamental challenges before a more complete model of the Universe can be achieved: i) What are the properties of the "dark matter" and "dark energy" that make up 96% of the Universe? ii) How do galaxies form and evolve? iii) What is the origin, and statistical nature, of structures in the Universe? This grant will address these fundamental problems through pioneering theoretical work and the use of new surveys of the sky to map billions of distant galaxies. Galaxies are the "building blocks" of the Universe and as well as studying how they form, we will use the galaxies to improve our understanding of cosmology (the properties of the Universe as a whole). We will exploit current and forthcoming galaxy surveys including the Dark Energy Survey, SDSS-IV, SERVS and Euclid to measure numerous probes of cosmology such as the clustering of galaxies, supernovae and weak gravitational lensing (distortions of the galaxies' shape due to gravity). Precise cosmological models will be constructed and analysed, and simulated with Portsmouth's SCIAMA supercomputer. These models will be compared to data to reveal the cosmological properties of the Universe. The surveys will be used to study how galaxies form, by measuring their colours and taking detailed spectra of the galaxies. We will also study the evolution of galaxies by comparing the galaxies in the nearby Universe, showing their present state, with those of the distant Universe, which gives us a window into the past.Bringing together all our work, we will model and measure the evolution of the Universe throughout its entire history. We will study how quantum fluctuations in the very early universe may be stretched by inflation in the very early universe to astronomical scales, leaving their imprint in the distribution of light and matter in the universe today. We will also explore the characteristic imprint of Einstein's general relativity and the role of dark energy in shaping the evolution of structure in our Universe. Additionally, our analyses will shed light on the properties of dark matter, which we can "see" via gravity but which does not interact like normal matter. We will also obtain a fuller understanding of the characteristics of galaxies throughout cosmic time. This will tell us whether the usual assumptions about dark matter provide an adequate description of the formation and evolution of galaxies.ICG staff are committed to public outreach and have been engaged in a number of high-profile activities in the media and local community. For example, our staff have visited many local schools to discuss their careers, their research, and share their enthusiasm for astrophysics and cosmology, e.g. BBC Stargazing Live for the last few years with thousands of participants