Discovery of potential gravitational lenses shows citizen science value
September 24, 2015
Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)
Around 37,000 citizen scientists combed through 430,000 images to help an international team of researchers to discover 29 new gravitational lens candidates through Space Warps, an online classification system which guides citizen scientists to become lens hunters.
Gravitational lens systems are massive galaxies that act like special lenses through their gravity, bending the light coming from a distant galaxy in the background and distorting its image. Dark matter around these massive galaxies also contributes to this lensing effect, and so studying these gravitational lenses gives scientists a way to study this exotic matter that emits no light.
Since gravitational lenses are rare, only about 500 of them have been discovered to date, and the universe is enormous, it made sense for researchers to call on an extra pair of eyes to help scour through the mountain of images taken from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). Details of the discoveries will be published in Monthly Notices of the Royal Astronomical Society.
“Computer algorithms have been somewhat successful in identifying gravitational lenses, but they can miss lensed images that appear similar to other features commonly found in galaxies, for example the blue spiral arms of a spiral galaxy,” said Anupreeta More, co-principal investigator of Space Warps and project researcher at the University of Tokyo’s Kavli Institute for the Physics and Mathematics of the Universe.
“All that was needed was the ability to recognise patterns of shapes and colours,” said citizen scientist and paper co-author Christine Macmillan from Scotland. “It was fascinating to look at galaxies so far away, and realize that there is another behind it, even further away, whose light gets distorted in an arc.”
Not only did this project give the public a chance to make scientific discoveries, it also gave them a chance to develop as researchers themselves. “I benefited from this project with an increase of my knowledge and some experience on making models of lenses,” said citizen scientist and paper co-author Claude Cornen from France.
More, and two other collaborators, Phil Marshall at the Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, and Aprajita Verma at the Department of Physics, University of Oxford, are co-principal investigators of Space Warps, which taps into the unique strength of humans in analysing visual information essential for finding gravitational lenses.
The team will now move onto studying some of the interesting gravitational lens candidates by observing them with telescopes to uncover some of the mysteries related to dark matter. They are keen to work together with more volunteers in the near future as they are preparing new images from other ongoing imaging surveys to discover many more lenses.
Journal: Monthly Notices of the Royal Astronomical Society (MNRAS)
Title: Space Warps II. New Gravitational Lens Candidates from the CFHTLS Discovered through Citizen Science
To download preprint, click here.
All images can be downloaded from this page: http://web.ipmu.jp/press/20150903-SpaceWarps
Full list of citizens who took part: http://spacewarps.org/#/projects/CFHTLS/contributors
To download preprint of another paper also accepted to MNRAS journal that describes the details of Space Warps, click here.
Press officer, Kavli Institute for the Physics and Mathematics of the Universe
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Project Researcher, Kavli Institute for the Physics and Mathematics of the Universe
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About Kavli IPMU
Kavli IPMU (Kavli Institute for the Physics and Mathematics of the Universe) is an international research institute with English as its official language. The goal of the institute is to discover the fundamental laws of nature and to understand the Universe from the synergistic perspectives of mathematics, astronomy, and theoretical and experimental physics. The Institute for the Physics and Mathematics of the Universe (IPMU) was established in October 2007 under the World Premier International Research Center Initiative (WPI) of the Ministry of Education, Sports, Science and Technology in Japan with the University of Tokyo as the host institution. IPMU was designated as the first research institute within the University of Tokyo Institutes for Advanced Study (UTIAS) in January 2011. It received an endowment from The Kavli Foundation and was renamed the “Kavli Institute for the Physics and Mathematics of the Universe” in April 2012. Kavli IPMU is located on the Kashiwa campus of the University of Tokyo, and more than half of its full-time scientific members come from outside Japan. http://www.ipmu.jp/