Due to the finite speed of light, these observations allow astronomers to look back in time over 10 billion years, producing images of galaxies in the Universe's infancy. The image is so large and so deep that thousands of galaxies can be studied at these early epochs for the first time. By observing in the infrared, astronomers can now peer further back in time, since light from the most distant galaxies is shifted towards redder wavelengths as it travels through the expanding Universe.
"I would compare these observations to the ice cores drilled deep into the Antarctic," said Dr Foucaud. "Just as they allow us to peer back in time, our ultra-deep image allows us to look back and observe galaxies evolving at different stages in cosmic history, all the way back to just 1 billion years after the Big Bang".
One of the key aims is to understand when the rarest, most massive galaxies form in the distant Universe, which is a long-standing unsolved problem in astronomy. "We see galaxies 10 times the mass of the Milky Way already in place at very early epochs. Now, for the first time, we are sampling a large enough volume of the distant Universe to be able to see them in sufficient numbers and really pin down when they were formed."
The image was obtained using the United Kingdom Infrared Telescope (UKIRT) in Hawaii. The results presented today form part of the Ultra-Deep Survey (UDS), led by Dr Omar Almaini at the University of Nottingham. The UDS is one element of a five-part project, the UKIRT Infrared Deep Sky Survey, which commenced in 2005. Professor Andy Lawrence, Principle Investigator of UKIDSS from the University of Edinburgh, said "As we keep taking images over the next few years, we will see ever more distant galaxies."
