Astronomers have used the Hubble space telescope to discover the faintest and most distant galaxies ever seen. A new camera fitted to the orbiting observatory in May by shuttle astronauts has captured dim red “star cities” that formed only 600-900 million years after the Big Bang.
The universe is thought to be around 14 billion years old and this new glimpse of them is a look back in time more than 13 billion years. Two teams from the universities of Oxford and Edinburgh picked out the candidates for most remote galaxies in images taken in infrared light by Hubble’s new Wide Field Camera 3.
It is an incredible photograph, covering a square patch of sky just a 15th the width of the full moon. Yet that tiny bit of the heavens alone is crammed with thousands of whirls and blurs – each one a collection of many millions or billions of stars.
The area of sky, in the southern constellation of Fornax, is the same as that photographed five years ago by the space telescope in a classic image that became known as the Hubble Ultra Deep Field. But the new picture is looking even further back in time, capturing the earliest hot young stars.
Astronomers hope that studying these most distant celestial objects will provide clues as to how galaxies formed in the earliest days of the universe. Previous distant galaxies have been recorded at a distance of around 13 billion light-years.
Stephen Wilkins, an astrophysics at Oxford University, said: “The expansion of the universe causes the light from very distant galaxies to appear redder, so having a new camera on Hubble which is very sensitive in the infrared means we can identify galaxies at much greater distances than was previously possible.”
Ross McLure, of the Institute for Astronomy in Edinburgh, said: “The unique infrared sensitivity of Wide Field Camera 3 means that these are the best images yet for providing detailed information about the first galaxies as they formed in the early universe.”
Daniel Stark, of the Institute of Astronomy in Cambridge, who contributed to the teams’ work, said: “We can now look even further back in time, identifying galaxies when the universe was only 5 percent of its current age – within 1 billion years of the Big Bang.”
Professor Jim Dunlop at the University of Edinburgh, said: “These new observations from HST are likely to be the most sensitive images Hubble will ever take, but the very distant galaxies we have now discovered will be studied in detail by Hubble’s successor, the James Webb Space Telescope, which will be launched in 2014.”
The British research is among 12 on the exciting new image published in British journal the Monthly Notices of the Royal Astronomical Society. Last month impressive pictures were released of the nearby Pinwheel Galaxy M83 using the Wide Field Camera 3. Hubble has taken other stunning images of galaxy groupings.
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