A flight to Europe to unravel the unknowns

13 April 2018

International collaborations are crucial in Science. They enhance the quality of research, accelerate progress, and often lead the work to new and unexplored paths. Prof Geraint Lewis knows it well:

"Nothing really beats sitting down and talking with somebody about a project, he said to Sydney Morning Herald.

Last February, Prof Lewis flew to Germany as ESO Scientific Visitor, bringing with him his expertise on gravitational lenses.

Predicted by Albert Einstein, gravitational lenses are one of the most exciting phenomenon in astronomy. According to the general relativity, the presence of matter can curve the spacetime and therefore, the path of light will be deflected producing patterns as shown by the diagram below.

Analysing the nature of these patterns can reveal the way matter (including dark matter) is distributed within galaxies and their distance from the Earth. But such analysis requires high-resolution images of galaxies.

Working with Prof Lewis was Prof Rob Ivison, the ESO Director for Science. Through new telescopes, ESP has access to a goldmine of new observations that reveals the universe with unprecedented details. Together, they worked on ALMA observation of gravitational lensing.

The two astronomers sat together with one goal in their mind "to understand the dark side of the universe - dark matter, dark energy. That kind of stuff".

Their goal is to unravel the secret of the unseen lens by study the pattern that they produce. Such lenses can be single galaxies or even group of galaxies, but despite their nature, they answer one of the most complexes questions in astronomy and cosmology: how much dark matter there is in these galaxies? And is it "smooth" or "lumpy"?

With the ESO data and with the help of supercomputers, Prof Lewis hopes to do become a step closer to answering these questions.

"The problem is what you are trying to do is infer the properties of something you can't actually see," Prof. Lewis says, "It's constant evidence gathering, which of course is what science is".

Prof Lewis describes his six weeks in Europe very productive:

"I've got a lot more done regarding ideas from sitting and chatting with people than I would have over many months of sending emails back and forth."

Part of his Sabbatical program is to increase the linkages between ESO and SIfA Astronomers. Last July, Australia signed a ten-year strategic partnership that guarantees to the ESO research infrastructure. Australia will pay for ten years of access with the potential to upgrade to full membership. If this will happen, explains Prof Lewis, Australian astronomers would have not only access to existing searches, but could also point the telescope where desire:

"The new opportunities offered are pretty big."

Prof Lewis will also be visiting the University of Surrey in June as a Santander Fellow, working with Dr Michelle Collins, an expert on the Local Universe, to unravel the dynamics of dwarf galaxies. These tiny galaxies are dominated by dark matter, and so continue Prof Lewis's quest to reveal the unseen.

Contact: Prof Geraint Lewis

Phone: 02 9351 5184

Email: 2513213442051b6b1d5c0f5e1b2d1f3f3c58031a4f2c2e347b1724