Astronomy at St Andrews 2018-2021

点击翻译按钮获取中文摘要

The St Andrews astronomy group is interested in questions of origins: where do galaxies, stars and planets come from, and what fundamental physics explains their formation? How widespread is life and how did it arise on Earth and on other worlds? We are world leaders in solving intricate mathematical problems, and we use novel methods such as observations at very high precision and simulations with super computers. We are joined by other groups across Scotland via the Scottish Universities Physics Alliance (SUPA), and internationally, in searching for hot and cool Earth-sized planets, homing in on habitable worlds where life could exist, and developing ways to detect life on those distant worlds.Our investigations span a wide range of size scales, from discovering planetary systems around stars a few light years away to measuring the force of gravity acting on the whole universe. We discover `hot Jupiters' by using robotic wide-angle cameras that monitor thousands of stars to find those that briefly dim each time an orbiting planet passes in front of its parent star. We measure the masses of these planets using high-precision spectrographs to measure how much the orbiting planet wobbles its host star. We discover cooler and smaller more Earth-like planets by using a global network of robotic telescopes to watch gravitational lenses, exploiting Einstein's prediction that a planet drifting across the sightline to a distant background star bends its light. We learn about how planets form by studying the light from the gas and dust grains that accumulate to form planets, comparing with our computer simulations to understand the chemistry may lead to formation of biological molecules.Young stars have strong magnetic fields that interact with orbiting planets and their own magnetic fields. We study the signatures of this interaction to understand how planets form and evolve. We investigate the physics of mineral clouds and lightning in atmospheres of cool brown dwarf stars and extrasolar planets, processes that may play a role in the origin of life. We compare observations and computer simulations to study how stars form in galaxies and how feedback from young stars drives a dynamic, bubbling interstellar medium, the dusty gas from which new stars are born. We include energetic supernova explosions when massive stars die and the ionising radiation from massive stars that heats the gas in the galaxy to temperatures above than 10,000 degrees Centigrade.On cosmological scales, we measure how gas and stars move within galaxies to study how galaxies form their characteristic shapes of flat discs, spiral arms and central bulges, and how these change as galaxies collide and merge to grow larger elliptical galaxies. We study the supermassive black holes that lurk in galaxy cores, to understand how they form and grow, and how their huge output of energy and radiation affects the host galaxy evolution. We study how gravity works both within galaxies and across the wider universe. Stars orbit in galaxies so fast that there appears to be too little mass to hold galaxies together, and our expanding universe appears to be accelerating. We understand gravity well enough to send space probes to other planets, but to understand these larger scale puzzles we investigate alternatives to current ideas of Dark Matter and Dark Energy, comparing our predictions with observations to test how gravity works.Thus we address all four of the STFC Science Roadmap Challenges: How did the Universe begin and how is it evolving? How do stars and planetary systems develop and is life unique to our planet? What are the fundamental constituents and fabric of the universe and how do they interact? How can we explore and understand the extremes of the universe? What are the laws of physics in extreme conditions? How do galaxies, stars and planets form and evolve? Are we alone in the Universe?