Pieces of warped galaxy
A team of scientists, led by The Open University, has made a breakthrough discovery of a new population of galaxies magnified by warps in space and time. The team found these galaxies in their first data from the European Space Agency's infrared space telescope, Herschel.
Lead researcher for the team doing this research, Mattia Negrello of The Open University, says: “What makes this breakthrough particularly exciting is that we were surveying a generic region of the sky and at wavelengths sensible to infrared emission rather than optical emission. The implication of our research is that the sky is littered with optically invisible clover leaf formations that are warped images of distant galaxies. Suddenly we have a wonderfully efficient new way of finding these rare places where we have this magnified view of very distant galaxies.”
These rare configurations happen where our line of sight to a background galaxy passes close to a nearer galaxy, and the warped space near the foreground galaxy magnifies the distant one.
Stephen Serjeant, Reader in Cosmology at The Open University says: "Everything in the Universe warps the space and time around it. It's a very weak effect for, say, a person, but for a giant elliptical galaxy half-way across the Universe it's a different matter. It has so much mass that its warped space clearly magnifies the view of even more distant things."
The research team predicted that by surveying such a large area of the sky in the infrared they would be able to spot these distant galaxies from their strong infrared brightness, caused by the magnification. Meanwhile, optical telescopes see only the foreground galaxy which is doing the warping and magnifying.
“We’ve used techniques that are much simpler and more efficient than ever before in order to make this breakthrough discovery,” says Mattia Negrello. “Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at sub-millimetre wavelengths for looking at the properties of dusty, star-forming galaxies. But the identification of gravitational lenses is often time consuming, involving sifting through large volumes of data. We used early data from the Herschel Astrophysical Terahertz Large Area Survey (Hershel-ATLAS) to demonstrate that wide-area infrared surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.”
The data was taken as part of ATLAS, a major undertaking by the Herschel telescope, covering Herschel's biggest volume of the Universe. Herschel-ATLAS is a collaboration of over 180 scientists in 10 countries, led jointly by Professor Steve Eales (Cardiff University) and Dr Loretta Dunne (University of Nottingham).
Professor Steve Eales, University of Cardiff said: "I am absolutely delighted that our wide-area survey is already reaping such spectacular rewards. What's more, this is just a taste of things to come. ATLAS will create by far the biggest catalogue of galaxies from Herschel and our survey has a tremendous scope for new discoveries, such as this."
The Open University is co-leading the gravitational lensing work within ATLAS, working with 39 other universities in Herschel-ATLAS. Their focus is dusty, star-forming galaxies that are often impossible to detect through optical telescopes.
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Notes to Editor
Images, including high quality lensing diagram, available on request.
Mattia Negrello is available for interview.
For more information, please visit:
Herschel-ATLAS website: http://www.h-atlas.org
About research at The Open University
The Open University supports a vibrant research portfolio and in the UK's latest Research Assessment Exercise (RAE 2008), it climbed 23 places to 43rd, securing a place in the UK's top 50 higher education institutions. Results showed that more than 50% of the OU’s research is internationally excellent (3*), with a significant proportion world-leading (4*).
The Open University’s Science Faculty is involved with international research programmes in biological and health sciences; chemistry; Earth, planetary and space sciences; and physics and astronomy. The depth and breath of OU science programmes attracts students to take over 43,000 science short courses each year.
Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.