Astronomy at St Andrews 2021 - 2024

Lead Research Organisation: University of St Andrews
Department Name: Physics and Astronomy

Abstract

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 extra-solar planets by using robotic wide-angle cameras and NASA's TESS space telescope to monitor thousands of stars and find those that briefly dim each time an orbiting planet passes in front of its parent star. We measure accurate
sizes for these planets by observing the transit light curves using ESA's CHEOPS space telescope, and determine the planet masses
using the high-precision HARPS 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 the 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 galaxy and 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.

Planned Impact

Our research creates two major kinds of impact, engagement with the public as well as knowledge exchange with industrial and interdisciplinary partners. A range of initiatives have been developed over the past few years, outlined in detail in the 'Pathways to Impact' section in the application document. Our activities are coordinated through a developing public engagement strategy supported by the School of Physics & Astronomy and the University of St Andrews.

In terms of public engagement, our work includes engagement with local schools, in particular those in deprived areas in Fife, participating in university-wide successful outreach programs, as well as presence at exhibitions and festivals. Our research work is widely and frequently presented in the national and world-wide media, both as news reports and features in major newspapers, magazines, radio, and TV stations. Members of our group have published several popular science books in recent years.

Four particular initiatives will be highlighted in the following. The university observatory, supervised by Scholz, is a key attraction for the public and hosts numerous events and open nights every year. In particular, the historic, and yet still active James Gregory Telescope, Scotland's largest telescope, attracts about 1000 visitors every year, with an ever-growing social-media presence.

The prominent project Shine, launched in 2015 and led by Weijmans, supported through an STFC Leadership Fellowship in Public Engagement, links science, arts, and music through a multi-faceted program. It includes among others the creation of new science-themed music as well as exhibits by local artist Tim Fitzpatrick.

The Scottish Sloan Digital Sky Survey Planets for Education project, led by Tojeiro, teaches astrophysical concepts to secondary school children, using the Sloan observing plates as hands-on material. Apart from school visits, this program delivers workshops for teachers. The project will expand in the following years.

Our mobile planetarium, run entirely by PhD students, visits local schools to enhance education in astronomy -- this is a long-standing initiative with a successful track record spanning more than 20 years.

In terms of Knowledge Exchange, we highlight here two particular initiatives:

First, we have a long standing collaboration with Ninewells Hospital in Dundee on photodynamic therapy for the treatment of skin cancer, using Monte Carlo simulations of light propagation through human tissue. Recently this has been extended to other projects including PDT for brain cancer, determining DNA damage due to tanning salons, in silico testing of new ultraviolet light sources for treating chronic skin conditions, and the effects of sunscreen on the build up of Vitamin D in skin.

Second, our local 0.94m James Gregory Telescope is used to discover space debris in geosynchronous and Molniya orbits, in collaboration with SpaceInsight, a company providing observations and tracking of man-made near-Earth objects, and supported by the UK Space Agency, the European Space Agency, and the Defense Science & Technology Laboratory. Building on this collaboration, we are currently installing a new remotely controlled telescope on the grounds of the observatory in St Andrews, supported by an STFC Impact Accelerator Grant.

Publications

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