The statistical era of strong gravitational lensing
Lead Research Organisation:
University of Portsmouth
Department Name: Institute of Cosmology and Gravitation
Abstract
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 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. I have used small samples of gravitational lenses to give preliminary answers to my three questions, and I have new data from the world's biggest telescopes to improve these answers.
The main limitation of my work is that there aren't enough lenses. Fortunately there is a giant new telescope forthcoming. It will find 100 times more lenses than are currently known. I lead the strong lensing efforts in this survey. Finding the lenses will be challenging as there are a million non-lenses for every lens. I am working on new discovery methods using computer vision algorithms, and volunteer citizen scientists. At the end of the ERF I will have enough lenses to answer my three questions and understand the accelerated 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. I have used small samples of gravitational lenses to give preliminary answers to my three questions, and I have new data from the world's biggest telescopes to improve these answers.
The main limitation of my work is that there aren't enough lenses. Fortunately there is a giant new telescope forthcoming. It will find 100 times more lenses than are currently known. I lead the strong lensing efforts in this survey. Finding the lenses will be challenging as there are a million non-lenses for every lens. I am working on new discovery methods using computer vision algorithms, and volunteer citizen scientists. At the end of the ERF I will have enough lenses to answer my three questions and understand the accelerated expansion of the Universe.
People |
ORCID iD |
| Thomas Collett (Principal Investigator / Fellow) |