28 Jun 2016

Astronomers at The University of Nottingham have released spectacular new infrared images of the distant Universe, providing the deepest view ever obtained over a large area of sky. The team, led by Omar Almaini, Professor of Astrophysics in the School of Physics and Astronomy, is presenting their results at the National Astronomy Meeting taking place this week at the University’s Jubilee Campus.

The final data release from the Ultra-Deep Survey (UDS) maps an area four times the size of the full Moon to unprecedented depth. Over 250,000 galaxies have been detected, including several hundred observed within the first billion years after the Big Bang. Astronomers around the world will use the new images to study the early stages of galaxy formation and evolution.

The release of the final UDS images represents the culmination of a project that began taking data in 2005. The scientists used the United Kingdom Infrared Telescope (UKIRT) on Hawaii to observe the same patch of sky repeatedly, building up more than 1000 hours of exposure time. Observing in the infrared is vital for studying the distant Universe, as ordinary starlight is "redshifted" to longer wavelengths due to the cosmological expansion of the Universe. 

Because of the finite speed of light, the most distant galaxies are also observed very far back in time.

Professor Almaini said: "With the UDS we can study distant galaxies in large numbers, and observe how they evolved at different stages in the history of the Universe. We see most of the galaxies in our image as they were billions of years before the Earth was formed.”

The UDS is the deepest of 5 projects, collectively known as the UKIRT Infrared Deep Sky Survey (UKIDSS).

Earlier releases of data from the UDS have already produced a wide range of scientific advances, including studies of the earliest galaxies in the first billion years after the Big Bang, measurements of the build-up of galaxies through cosmic time, and studies of the large-scale distribution of galaxies to weigh the mysterious ‘dark matter’ that pervades the cosmos. The added depth from the new release is expected to produce many new breakthroughs.

Dr David Maltby, a postdoctoral research fellow at The University of Nottingham whose research focusses on morphological evolution of galaxies, said: "Here in Nottingham we are aiming to understand how galaxies evolved to produce the rich diversity we see today. For example, we still don't understand why the most massive galaxies are usually elliptical in shape, while less massive galaxies tend to be disk-shaped with spiral arms. By looking back in time to the early Universe we can catch these galaxies in their infancy, and observe them as they change and evolve over many billions of years."

UKIRT

The 3.8-metre United Kingdom Infrared Telescope (UKIRT) is the world’s second largest telescope dedicated to infrared astronomy. UKIRT is sited near the summit of Mauna Kea, Hawaii, at an altitude of 4194 metres (13760 feet) above sea level. The telescope was owned and operated by the UK Science and Technology Facilities Council until 2014, when ownership transferred to the University of Hawaii.

UKIDSS

The UKIRT Infrared Deep Sky Survey (UKIDSS) is a large astronomical project that began in 2005, using most of the available observing time on the United Kingdom Infrared Telescope (UKIRT). UKIDSS consists of 5 separate surveys, from shallow mapping of large areas of sky to deeper studies of the distant Universe. The UDS is the deepest of the UKIDSS surveys.