Professor Stephen Smartt: Evolving the Cosmos
ERC Project: “Ultraluminous Supernovae: Origins and Cosmic Evolution” To find ultraluminous supernovae and help quantify the physical nature of these unusually brilliant stellar explosions.
Mapping New Horizons
Supernovae have been known about for the last 70 years, but only in the last five-to-10 years have researchers become aware of ultraluminous supernovae, which are 100 times more luminous that normal supernovae.
Stephen holds an ERC Advanced Grant (2012–2017) for work on ultraluminous supernovae and the stars that produce them. He leads a team who hunt the skies for these elusive yet super-bright stellar events.
Over five years the ERC grant of 2.3 million euro is one of the biggest individual grants awarded in Europe and UK funding schemes.
Starman: Professor Stephen Smartt
Stephen studied for a degree in Physics and Applied Maths and a PhD in Astrophysics at Queen’s. He was an astronomer at the UK observatory in La Palma – at 2,400 metres above sea-level, the best place in Europe to study the sky. After postdoctoral study and a fellowship at Cambridge, in 2004 he took up a lectureship at Queen’s. He is currently Director of the Astrophysics Research Centre in Queen’s School of Mathematics and Physics.
Life and Death in Galactic Proportions
Supernovae are the deaths of massive stars. When stars more massive than 10 times the mass of the sun reach the end of their lives their cores collapse releasing huge amounts of energy. Supernovae explosions produce the critical chemical elements for life, such as oxygen, carbon, nitrogen, magnesium and silicon. Neutron stars are the densest form of matter we know: a density equatable to every person on the planet being squeezed onto a teaspoon.
Eye on the Sky
Take large telescopes on earth, search large areas of sky, find exploding stars.
A key part of the project is the Pan-STARRS telescope in Hawaii (Pan-STARRS = Panoramic Survey Telescope and Rapid Response System). It’s the biggest camera for civilian use at 1.4 giga pixels and seven square degrees of sky, or an area seven full moons, in diameter.
Explosive Explanations: Magnetars as Engines
Most massive stars rotate quickly and when their cores collapse they will produce rapidly spinning neutron stars, which we see throughout the galaxy. If they also posses a high magnetic field, the rotational energy can be converted to radiation and will boost the supernova explosion to “ultraluminous” proportions. This magnetic neutron star (magnetar) model is now the most popular explanation and fits the data from this project very well.
Big Data, Big Discovery
Taking data from the Pan-STARRS at Haleakala in Hawaii, Queen’s High Performance Computing Centre crunches data 24/7, 365 days a year, cross-referencing daily every known object in the scannable universe. Last year, the project found 3,000 supernovae. Queen’s is sharing these data with scientists around the world.
“Only around once in 100 years is a supernova seen in our own galaxy. Look at 100 spiral galaxies for a year and one supernova might be found. We look at tens of thousands of galaxies at any one time.” (Professor Stephen Smartt)
Superstars of Research
An Oxford undergraduate, Matt Nicholl came to Queen’s to study for his PhD under Professor Smartt. Part-funded by ERC grant money, Matt was awarded The Royal Astronomical Society’s Prize for Best Thesis in 2015. The ‘Michael Penston Prize’ is a UK-wide prize for the best thesis in astronomy or astrophysics in a given year.
“We were studying a mysterious type of extremely rare superluminous supernova explosion. I think it is fair to say that many of the most important results in this topic have come from the QUB group.” (Matt Nicholl)
This international ERC team included Dr Cosimo Inserra, from Italy, who won the Royal Astronomical Society Winton Capital award for his work on the project. Dr Anders Jerkstrand, from Sweden, went on to win a Marie Curie fellowship and Dr Ting Wan Chen, from Taiwan, won a Humboldt Fellowship in Munich.
The project published over 100 referred papers (including two in Nature) with 3000 citations to date, and has had a major impact in the field.
The Greatest Movie Ever Made
Astronomers at Queen’s University will lead efforts around the world to search for exploding stars, comets and potentially hazardous asteroids. To do this they will use the Large Synoptic Survey Telescope (LSST) – the world’s largest digital camera. For the first time, images of billions of galaxies, stars and solar system objects will come together to form the first motion picture of our Universe.
“Experts from Queen’s will lead the UK effort to find distant supernovae – exploding death stars – which hold the key to understanding the origin of the chemical elements of the periodic table and the size and geometry of the Universe.”
Making Gravitational Waves
"Gravitational waves have just been discovered. What we want to do now is find optical or electro-magnetic radiation that is also produced by these merging black holes and neutron stars” (Professor Stephen Smartt)
Thinking Like Humans
Analysis techniques used to cross-reference the sky and disseminate data are now being applied to big data problems and to develop machine learning to make computers think more like humans. The team hope to apply these image-recognition tools to other fields, such as to medical imaging to make scanning more robust and efficient.