UK scientists use Euclid spacecraft to probe mysteries of dark Universe

The European Space Agency's Euclid mission launched in July 2023 to map the ‘dark Universe'. This involves observing two billion galaxies to create a 3D map of the universe and gathering data on how its structure has formed over its cosmic history. 

The images and science released today represent early findings – from only 24 hours of observations – giving a glimpse into the power of Euclid to hunt for new planets, study dark matter and answer fundamental questions.    

Dr Caroline Harper, Head of Space Science at the UK Space Agency, said:  

A key part of our purpose as a space agency is to understand more about the Universe, what it's made of and how it works. There is no better example of this than the Euclid mission - we know that most of Universe is made up of invisible dark matter and dark energy, but we don't really understand what it is, or how it affects the way the universe is evolving.

Science missions like Euclid generate vast quantities of valuable data for scientists across the world, and UK researchers have played a leading role in the development of the mission and in delivering these early results, less than a year after launch.

The scientific papers include one by Professor Mark Cropper from UCL Mullard Space Science Laboratory, who led on designing and developing the VIS optical camera over 16 years, working with teams at UCL, Open University and across Europe.  

The paper gives an overview of Euclid's VIS optical camera, which is one of the largest ever sent into space and supported by £20 million of UK Space Agency funding.  

Professor Mark Cropper said:  

These are the largest images of the Universe ever taken from space, covering large swathes of the sky in fine detail. They demonstrate Euclid's wide-ranging potential, from discovering new planets to surveying vast clusters of galaxies.  

To achieve its core aim of better understanding dark energy and dark matter, Euclid's measurements need to be exquisitely precise. This requires a camera that is incredibly stable, incredibly well understood, with conditions inside it needing to be controlled very carefully. The VIS camera we developed will not only contribute beautiful images, but help us answer fundamental questions about the role of dark energy and dark matter in the evolution of the Universe.

Another paper from Professor Nina Hatch at the University of Nottingham, examines a group of galaxies known as the Perseus Cluster. The Perseus Cluster is located 240 million light-years away from Earth and contains thousands of galaxies, immersed in a vast cloud of hot gas. It's a key target for research as galaxy clusters like this can could only be formed with the presence of dark matter.  

Professor Nina Hatch said:  

Euclid's images of the Perseus cluster revealed a faint glow between the galaxies, known as intracluster light. This light can help us map dark matter if we understand where the intracluster stars came from. By studying their colours, luminosity, and configurations, we found they originated from small galaxies, which is surprising since theories suggest they should come from massive galaxies.  

This discovery moves us closer to using intracluster light to study dark matter. Our work supports Euclid's mission to understand dark energy and dark matter, especially in forming structures like the Perseus cluster.

In addition to the VIS instrument, the UK is also playing a major role in the Euclid Science Ground Segment, which processes the data returned from the telescope into science ready products. A consortium of UK universities led by the University of Edinburgh provides the weak lensing data processing pipelines, a critical element of the mission's science. 

Professor Andy Taylor from the University of Edinburgh, who leads the UK's Euclid data analysis team and the Euclid gravitational lensing data analysis, said: 

These new images from Euclid are absolutely stunning. They demonstrate both the image quality and the huge area of the sky seen by Euclid in each observation. The image of the galaxy cluster, Abell 2390, is a spectacular demonstration of Euclid's ability to carry out the highest quality gravitational lensing survey we had hoped for. Each of the images are rich in information which we are only starting to mine. This is just a taster of what Euclid will do.

Teledyne e2v, based in Chelmsford, provided the telescope's Charged Couple Device detectors under a major industrial contract with the European Space Agency.  

Antonio Spatola, Director of Business Development and Sales, Teledyne e2v said: 

We are privileged to contribute the enabling technology to this important science mission. Teledyne Space Imaging has 36 CCD273-84 visible sensors which is 600 million pixels on the VIS instrument. We also have 16 H2RGs infrared sensors of more than 66 million infrared pixels on the NISP. Euclid has since delivered its dazzling images of the cosmos demonstrating the ability of our sensors to create remarkably sharp visible and infrared images.

 Together these activities mean end-to-end UK involvement in the mission, from photon measurement and data processing to cosmology. 

ESA Director General Josef Aschbacher said: 

Euclid demonstrates European excellence in frontier science and state-of-the-art technology, and showcases the importance of international collaboration.  

The mission is the result of many years of hard work from scientists, engineers and industry throughout Europe and from members of the Euclid scientific consortium around the world, all brought together by ESA. They can be proud of this achievement – the results are no small feat for such an ambitious mission and such complex fundamental science. Euclid is at the very beginning of its exciting journey to map the structure of the Universe.