Navigation path

Themes
Agriculture & food
Energy
Environment
ERA-NET
Health & life sciences
Human resources & mobility
Industrial research
Information society
Innovation
International cooperation
Nanotechnology
Pure sciences
Research infrastructures
Research policy
Science & business
Science in society
Security
SMEs
Social sciences and humanities
Space
  Galileo
  Space exploration
  Space hardware
  Space policy
  Teledetection
  Other
Special Collections
Transport

Countries
Countries
  Argentina
  Australia
  Austria
  Belarus
  Belgium
  Benin
  Brazil
  Bulgaria
  Cameroon
  Canada
  Chile
  China
  Colombia
  Croatia
  Cyprus
  Czech Republic
  Denmark
  Egypt
  Estonia
  Finland
  France
  Georgia
  Germany
  Ghana
  Greece
  Hungary
  Iceland
  India
  Ireland
  Israel
  Italy
  Japan
  Kazakhstan
  Kenya
  Korea
  Latvia
  Lithuania
  Luxembourg
  Malta
  Mexico
  Montenegro
  Morocco
  Namibia
  Netherlands
  Nigeria
  Norway
  Peru
  Poland
  Portugal
  Romania
  Russia
  Senegal
  Serbia
  Slovakia
  Slovenia
  South Africa
  Spain
  Swaziland
  Sweden
  Switzerland
  Taiwan
  Tunisia
  Turkey
  Ukraine
  United Kingdom
  United States


   Space

Last Update: 19-11-2010  
Related category(ies):
Space  |  Pure sciences

 

Add to PDF "basket"

New way of finding cosmic lenses facilitates study of distant galaxies

A European team of astronomers has discovered a new way of finding cosmic zoom lenses which allow astronomers to peer at galaxies in the distant universe. The ability to study galaxies — that were until now deemed too far away to investigate — will provide key insights into how galaxies have changed over the history of the cosmos, according to the researchers. The results, taken from the very first data revealed by the European Space Agency's Herschel-ATLAS (Astrophysical Terahertz Large Area Survey) project, were recently published in the journal Science.

The main image shows the first area of sky viewed as part of the Herschel ATLAS survey ©S.J.Maddox, H-ATLAS/ESA
The main image shows the first area of sky viewed as part of the Herschel ATLAS survey
© S.J.Maddox, H-ATLAS/ESA

The cosmic lenses were discovered by the European Space Agency's (ESA) Herschel Space Observatory that looks at far-infrared light emitted not by stars, but by the gas and dust from which they form.

Dr Mattia Negrello from the UK's Open University and lead researcher of the study said: 'Our survey of the sky looks for sources of sub-millimetre light. The big breakthrough is that we have discovered that many of the brightest sources are being magnified by lenses, which means that we no longer have to rely on the rather inefficient methods of finding lenses which are used at visible and radio wavelengths.'

The Herschel-ATLAS images contain thousands of galaxies, most so far away that the light has taken billions of years to reach us. Dr Negrello and his team investigated five surprisingly bright objects in a small patch of sky. By looking at the positions of these bright objects with optical telescopes on the Earth, they found galaxies that would not normally be bright at the far-infrared wavelengths observed by Herschel. This led them to suspect that the galaxies seen in visible light might be gravitational lenses magnifying much more distant galaxies seen by Herschel.

Dr David Bonfield from the University of Hertfordshire in the UK used visible and near-infrared measurements taken from existing visible images to estimate the distances to the galaxies believed to be acting as lenses. 'More distant galaxies have their light stretched to longer, redder wavelengths, because the light travels through more of the expanding universe before reaching us,' he explained. 'So we can use the colours they appear to figure out how far away they are.'

To find the true distances to the Herschel sources behind the lenses, Dr Negrello and his team looked for a tell-tale signature of molecular gas. Using radio and sub-millimetre telescopes on the ground, they showed that this signature implies that the galaxies are being seen as they were when the universe was between only 2 and 4 billion years old, less than a third of its current age. The galaxies seen by the optical telescopes are much closer, each ideally positioned to create a gravitational lens.

'Previous searches for magnified galaxies have targeted clusters of galaxies where the huge mass of the cluster makes the gravitational lensing effect unavoidable,' said Dr Negrello. 'Our results show that gravitational lensing is at work in not just a few, but in all of the distant and bright galaxies seen by Herschel.'

Astronomers at the University of Hertfordshire said there would be 'many more exciting results to come' as the survey continues. The Herschel ATLAS project was awarded 600 hours of Herschel observation time to survey 550 square degrees of sky. It is expected to detect approximately 250 000 galaxies, from the nearby universe out to more distant galaxies when the universe was only around 2 billion years old. The Herschel space observatory was launched in May 2009 and, according to researchers, is now in a routine science phase. It will continue observing until its liquid helium coolant runs out in around 2.5 years. Last year, TIME Magazine voted Herschel the seventh best invention of 2009.


Convert article(s) to PDF

No article selected


loading


Search articles

Notes:
To restrict search results to articles in the Information Centre, i.e. this site, use this search box rather than the one at the top of the page.

After searching, you can expand the results to include the whole Research and Innovation web site, or another section of it, or all Europa, afterwards without searching again.

Please note that new content may take a few days to be indexed by the search engine and therefore to appear in the results.

Print Version
Share this article
See also

Herschel ATLAS
ESA
Science





  Top   Research Information Center