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Astronomers receive grant to explore the sky

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12.08.2005

Astronomers from the universities of Hertfordshire and Kent have received a grant which will allow them to map large areas of the sky 1000 times faster than with current technology.

The universities, in conjunction with the University of British Columbia and the Joint Astronomy Centre, have been awarded 1,500 hours of observation and survey time on the James Clerk Maxwell Telescope (JCMT) at the Mauna Kea Observatories in Hawaii. The award, which is part of the JCMT Major Legacy Surveys, has been valued by the Particle Physics and Astronomy Research Council (PPARC) at £2.1 million.

The study, which will begin in 2006 and end in 2011 and is known as SASSy (SCUBA-2 All-Sky Survey), intends to search a large fraction of the sky for unknown and invisible star-forming clouds and galaxies. A new £12 million SCUBA-2 camera within the telescope will allow the academics to access the cold hidden universe of distant dusty star-forming galaxies and nearby cold star-forming clouds.

The Hertfordshire team will lead the galactic (Milky Way) part of the survey, while those from Kent will lead the extragalactic (beyond the Milky Way) exploration.

Dr Mark Thompson from the Centre for Astrophysics Research at the University of Hertfordshire commented: “SCUBA-2 works in the sub-millimetre range of the spectrum and picks out objects that are not usually seen by optical telescopes. What this means is that for the first time we have a camera that can find practically all of the star-forming regions within our own Galaxy by imaging most of the entire sky."

Dr Stephen Serjeant from the Centre of Astrophysics and Planetary Science at the University of Kent added: “I have always been interested in the most extreme, most luminous galaxies in the Universe, but finding them is difficult, because they are very rare and often very distant. The SCUBA-2 instrument can find these galaxies almost all the way back to the Big Bang. Our enormous survey with the JCMT will map most of the northern sky, and look back through almost all the history of the Universe to find them.”

(1) With a diameter of 15m the James Clerk Maxwell Telescope (JCMT) is the largest astronomical telescope in the world designed specifically to operate in the sub-millimetre wavelength of the spectrum (which is roughly 100 times longer than the light the human eye sees. The JCMT is used to study our solar system, interstellar dust and gas, and distant galaxies.

(2) Mauna Kea (‘White Mountain’) is a dormant volcano on the island of Hawaii, the largest and southernmost of the Hawaiian Islands. It is located about 300 km (190 miles) from the capital city, Honolulu, on the island of Oahu. The highest point in the Pacific Basin, and the highest island-mountain in the world, Mauna Kea rises 9,750 m (32,000 ft) from the ocean floor to an altitude of 4,205 m (13,796 ft) above sea level, which places its summit above 40 percent of the Earth’s atmosphere.

(3) Mauna Kea is unique as an astronomical observing site. The atmosphere above the mountain is extremely dry -- which is important in measuring infrared and sub-millimetre radiation from celestial sources – and cloud-free, so that the proportion of clear nights is among the highest in the world. The exceptional stability of the atmosphere above Mauna Kea permits more detailed studies than are possible elsewhere, while its distance from city lights and a strong island-wide lighting ordinance ensure an extremely dark sky, allowing observation of the faintest galaxies that lie at the very edge of the observable universe. A tropical inversion cloud layer about 600 m (2,000 ft) thick, well below the summit, isolates the upper atmosphere from the lower moist maritime air and ensures that the summit skies are pure, dry, and free from atmospheric pollutants.

Helene Murphy | Source: alphagalileo
Further information: www.herts.ac.uk

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