A team of British astronomers from Imperial College, the Universities of Edinburgh, Cambridge and Sussex, and University College London, is announcing the first results of a new survey of the sky at submillimetre wavelengths, which promises to unveil the birth of galaxies and the rates of star formation through the history of the universe. A speaker on Wednesday 16th August at a symposium as part of the International Astronomical Union meetings in Manchester, the leader of the team, Professor Michael Rowan-Robinson of Imperial College, says, ‘We think we have found the way to demonstrate that, when we observe at submillimetre wavelengths and look for galaxies, we mainly find very distant star-forming galaxies. Two thirds of all the energy ever generated in nuclear processes in stars is emitted as submillimetre radiation, so observations at these wavelengths are vital for tracing the history of star formation in the universe.’

The team uses the UK’s SCUBA submillimetre camera on the James Clerk Maxwell Telescope in Hawaii to look for relatively bright cosmic sources emitting radiation at a wavelength of 850 microns. These sources are then studied with the French-German submillimetre array telescope at the Pic du Bure in France to locate their exact position on the sky. So far, the first sources studied in this way cannot be seen at all on deep images taken with ordinary visible light in the same direction. This demonstrates that they are incredibly distant galaxies, at high redshift.

Michael Rowan-Robinson has also calculated the emission expected from galaxies at a range of wavelengths from optical to submillimetre, from the earliest times (11 billion years ago, just 1 billion years after the Big Bang) to the present. By combining these calculations with survey results at optical, infrared and submillimetre wavelengths, the history of star formation in the universe is now being uncovered. Prof. Rowan-Robinson says, ‘For the first billion years of the life of the universe, the star formation rate in galaxies built up steadily to a level over ten times higher than it is today. It continued at that rate for several billion years. During that period most of the chemical elements that we and the Earth are made of were created inside stars and subsequently blasted out into space when the stars died in spectacular explosions. By the time the Sun and Earth formed 4.5 billion years ago, the rate of star formation had dropped to only about 3 times what it is today.’

Notes for Editors


Prof. Michael Rowan-Robinson, Imperial College London
phone: +44 (0)20 7594 7530

UK Submillimetre Survey team:

Imperial College: Michael Rowan-Robinson, Steve Serjeant, Andreas Efstathiou, Matthew Fox
University of Edinburgh: James Dunlop, John Peacock, Bob Mann, Andy Lawrence
University of Cambridge: Andrew Blain, Malcolm Longair
University of Sussex: Seb Oliver
University College London: Rob Ivison
INAOE, Pueblo, Mexico: David Hughes

Results are to be published in the Monthly Notices of the Royal Astronomical Society, 2000 (M.Fox et al)

Star Formation history models: results submitted to the Astrophysical Journal (M.Rowan-Robinson)