Image of a galaxy

Dr Thomas Collett will research the warping of spacetime around massive galaxies and measure the expansion rate of the Universe

28 April 2020

5 min read

A talented cosmologist in the early stages of his career has been awarded a five-year fellowship to help realise his research ambitions.

Dr Thomas Collett, from the University’s Institute of Cosmology and Gravitation, is one of only 10 researchers in the UK to receive an Ernest Rutherford Fellowship from the Science and Technology Facilities Council (STFC).The fellowship will allow Dr Collett to research the warping of spacetime around massive galaxies to learn about the large scale properties of the Universe. It will also enable him to measure the expansion rate of the Universe, the constituents of the Universe and to test if Einstein's general relativity is the correct theory of gravity on astronomical scales.

Dr Collett said: “The expansion of the Universe is getting faster and we don't know why. To solve this mystery I am using an effect called ‘gravitational lensing’ to answer the following three questions: How fast is the Universe currently expanding? How does gravity work over astronomical distance scales? What is the dominant component of the Universe's energy budget?”

Gravitational lensing occurs when two galaxies are aligned on the sky to about 1/3600 of a degree. The mass of the foreground galaxy warps spacetime and deflects the light from the background galaxy as it passes. A gravitational lens is where multiple images of the background galaxy are seen. The image separation is sensitive to the mass of the foreground galaxy, the way gravity works and the expansion of the Universe.

Gravitational lensing occurs when two galaxies are aligned on the sky to about 1/3600 of a degree. The mass of the foreground galaxy warps spacetime and deflects the light from the background galaxy as it passes. A gravitational lens is where multiple images of the background galaxy are seen. The image separation is sensitive to the mass of the foreground galaxy, the way gravity works and the expansion of the Universe.

Thanks to the funding, I'll be in the best position to answer the big questions of cosmology.

Dr Thomas Collett, Astrophysicist and cosmologist

Dr Collett has used small samples of gravitational lenses to give preliminary answers to his three questions, and now he has new data from the world's biggest telescopes to improve these answers.

He said: “This fellowship gives me secure funding to focus entirely on my research for five years. With this funding I will be able to take a leading role in the next generation of astronomical surveys which are coming online in the early 2020s. For my science these surveys will be 100 times better than existing surveys. 

“Thanks to the funding, I'll be in the best position to use these datasets to answer the big questions of cosmology. The fellowship should also be a launchpad for my career, enabling me to secure a permanent academic position that will allow me to continue my astrophysics research beyond the end of this fellowship.”

At the end of the five years, Dr Collett should have enough lenses to answer his three questions and understand the accelerated expansion of the Universe.

The STFC scheme provides funding for research programmes and encourages talented researchers, in UK universities, to remain in the country and at the same time attracts outstanding overseas researchers to the UK. 

Professor Mark Thomson, Particle physicist and Executive Chair of STFC, said: “Through these prestigious fellowships, STFC supports the very best researchers at a relatively early stage in their careers, enabling them to build on their already excellent research.

 The aim is to attract the most talented and innovative scientists from the UK and abroad. These awards also enable the Fellows to advance their careers by further developing their independence and leadership. The Ernest Rutherford Fellows play an important role in advancing the STFC science programme at the highest levels.”

All fellows who have completed their fellowship since 2009 are employed and more than 90% hold permanent jobs immediately following the completion of their fellowship. STFC awards the fellowships once a year. Find out more here.