Astrophysics, Cosmology and Gravitation at Portsmouth 2022-2025

This consolidated grant will support research in astrophysics, cosmology, and gravitation at the Institute of Cosmology and Gravitation (ICG) in the University of Portsmouth. The ICG was formed in 2002 through a strategic investment from the university and now hosts more than 60 researchers making it one of the largest extragalactic astronomy groups in the UK. Portsmouth was ranked 8th in terms of quality of physics research outputs in the Research Excellence Framework 2014.

Cosmology and astrophysics are experiencing a golden age of discovery-driven by new astronomical surveys and theoretical advances, and the recent detection of gravitational waves from inspiralling black holes and neutron stars. 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. We will exploit current and forthcoming galaxy surveys like DESI, 4MOST, SDSS, the Vera Rubin Observatory and Euclid to quantify the Universe using complementary probes such as the clustering of galaxies, supernovae and weak gravitational lensing. These data will be complemented with new gravitational wave observations from the LIGO and VIRGO experiments. 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 true nature of the Universe.

Our work will help us understand and measure the evolution of the Universe throughout its entire history. We will bring together constraints from several cosmological probes, combining measurements from weak lensing, galaxy clustering, supernovae and HI intensity mapping to chart the cosmic expansion and structure formation over time. We will study how quantum fluctuations in the very early universe may be stretched by cosmic inflation 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 or alternative gravity theories 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 obtain a fuller understanding of the characteristics of galaxies throughout cosmic time. We will study the origin of the supermassive black holes at the centre of primaeval galaxies and the first quasars, and trace their merger history through the detection of gravitational waves. We will use astronomical surveys to understand how galaxies form by studying their stellar contents in ever greater detail.

ICG staff are committed to engaging the public in their research, e.g., online citizens science projects like Supernova Hunter and Gravity Spy. In addition, our staff visit many local schools and colleges, and run an annual Stargazing event at Portsmouth Historic Dockyard for hundreds of participants. We also seek innovation from our research, using our skills and experiences to develop novel solutions to everyday problems, e.g. detecting faulty smart meters, improving emergency room care, and training the next generation of data scientists.