Queen's University Belfast Astronomy Observation and Theory Consolidated Grant 2017-2020

Supernovae create the heavy chemical elements we see in our solar system, the Galaxy and entire visible Universe. While stars evolve over millions or billions of years, a supernova explosion happens in seconds and the glowing remnant lasts for years. We aim to understand how these explosions happen and how they create the neutron stars, pulsars and black holes in our galaxy. The cores of massive stars collapse at the end of their nuclear burning life and the gravitational potential energy released drives an explosion through the interaction of neutrinos with the dense inner region of the star. How the most massive stars explode, and if a black hole is formed, is uncertain and there is a huge diversity in the energy observed in the known supernova population. Our proposed work will address these questions along with trying to find the sources that may create gravitational waves in the Universe. The most likely sources are merging neutron stars or black holes and it is expected that gravitational waves will finally be found. The question will then turn to finding the sources. The thermonuclear supernovae that are used as cosmic yardsticks and led to the Nobel Prize winning discovery of dark energy come from white dwarf stars. But how they explode and what the progenitor systems are still eludes us. Competing models of two merging white dwarfs, or single white dwarfs with a normal stellar companion are still feasible. Most likely there are several ways to explode a white dwarf - a star greater than the mass of the sun, but the size of the earth. We are in an excellent position to make advances in these areas with our theoretical computer codes and world leading sky survey data.

The elements created in supernovae form planetary systems in our galaxy - iron, silicon, oxygen, magnesium are all critical to forming planetary systems. The diversity in the known planetary systems around other stars in our galaxy (called exoplanets) is astounding. We know of thousands of exoplanets, with massive hot jupiters, multiple planetary systems and super-earths now commonly found. We can see planet formation in the disks of young stars during their first few million years of life. The latest large facility built in the southern hemisphere (ALMA), has provided spectacular data on proto-planetary disks and our work on the chemistry of the disk aims to understand their origins. Our work will probe the atmospheres of these distant worlds by carefully extracting the light that passes from the parent star through the atmosphere of the planet. We can also measure the ages of stars to set constraints on how planetary systems evolve with time and what the constraints for life bearing planets may be. The top priority in this area is to find another earth like planet - the right size, age and distance from its parent star to support an atmosphere and liquid water. This search requires careful consideration and tests of the methods to extract the tiny signals we expect and we propose to develop this with an eye on the future prize of detecting an earth twin.

A critical part of astrophysics is pulling together our detailed knowledge of physics that we can measure on earth to what we can only see (through electromagnetic radiation) in the distant Universe. This will be done through computer calculations of model atoms. These codes calculate how electrons are excited in atoms and ensures that astrophysics codes identify the elements that cause the spectral lines and features we see in supernovae, supermassive black holes, galaxy spectra and stars. Finally, we propose to run a novel experiment to use the UK's most powerful laser (the VULCAN facility) to mimic the physics of gas at the centre of a galaxy. The laser can produce a large enough x-ray flux that the conditions are equivalent and we, for the first time, can test the world's leading computer code that is used to model the central regions of galaxies close to their black holes.

We have an active and energetic outreach and engagement programme to target audiences locally in Northern Ireland and nationally in the UK. Highlights of our UK national media presence are appearances on Horizon, the Sky at Night, BBC Radio 4/5/World (typical audience figures 1 - 10 million for these appearances). To increase the public awareness of science in Northern Ireland we have made a focused effort to engage with the local media (BBC and independent broadcasters) to showcase our research highlights and related public events. Over the last 4-5 years we have had over 50 appearances on BBC Northern Ireland (radio and TV), RTE (Republic of Ireland National broadcaster) or other regional broadcasts. These are often the primary BBC news and magazine shows in the weekday morning and evenings, with typical listening figures of 295,000 for the morning and evening radio shows and 140,000 for TV. Highlights and examples of our outreach work are :

We have a £200k philanthropic donation from Dr. Michael West to enhance our engagement with the public and increase scientific awareness in this region. This funds a public lecture series and a research/outreach fellow.

A partnership with the W5 Discovery Centre (Ireland's award winning science and discovery centre at the Odyssey Arena in Belfast).

We host, support and sponsor bi-monthly meetings of the Irish Astronomical Association (IAA) at Queen's which brings in around 80 people each meeting. ARC staff regularly give lectures and use our influence to bring in speakers from Britain and Europe

We have hosted science events attracting large audiences: "Jupiter Watch" as part of the BBC's Stargazing live over the past 4 years, the 2015 partial solar eclipse, each of which had attendances in the range 400-600.

We hosted the STFC roadshows "The Large Hadron Collider exhibition" (including an evening with Peter Higgs) and "Seeing the Universe in all its light" (with a public lecture by Jocelyn Bell Burnell). These jointly attracted 1500 schoolchildren and members of the general public.

Astronomy lectures and presentations at: (i) QUB Horizons in Physics (which attracts around 400 Year 11-12 students per annum), (ii) Physics Open Days (around 200 Y13 students), (iii) Physics Teachers Conference. Talks at schools, mostly at secondary level but also at primary level (we actively take part in STEPS: Science and Technology Experts in Primary Schools) either in the classroom or at QUB. ARC staff typically deliver a total of about 40 schools talks annually to pupils.

The impact of all this has been a major increase in the appearance of scientists in the media in this UK region, but also a direct and tangible increase in the number of school students taking physics further. Over the last 4 years we have seen an increase in the number of UCAS applications from Northern Ireland students to physics based courses across the UK of 71% (acceptances up by 56%; details in Pathways to Impact document).

We have knowledge exchange programmes through our atomic data and image analysis research programmes. The work of Ballance, Ramsbottom and Keenan in atomic structure and collisional R-matrix calculations has a wider impact beyond the sphere of astrophysical plasmas (see Projects 4.1 and 5.1). The interpretation of spectra from magnetically confined plasma devices such as tokamaks (e.g. at JET) employs many of the same theoretical methods, but for widely different temperature and density parameters

As part of the data processing of Pan-STARRS (see Projects 1.1 and 1.2) we have developed novel machine learning algorithms for image recognition. This has led to interest from medical imaging researchers in cancer and molecular pathology and we are currently discussing applications of this in the biomedical fields with them. Dell and NVIDIA are interested in proof of concept demonstrations of very fast image recognition (our software) with their new hardware.