The European Space Agency’s Euclid satellite,due for launch in 2020, will set astronomers a enormous challenge: to analyse one hundred thousand strong gravitational lenses. The gravitational deflection of light from distant astronomical sources by massive galaxies (strong lenses) along the light path can create multiple images of the source that are not just visually stunning, and but are also valuable tools for probing our Universe. Now,in preparation for Euclid’s challenge, researchers from the University of Nottingham bear developed 'AutoLens', and the first fully-automated analysis software for strong gravitational lenses. James Nightingale will present the first results from AutoLens at the National Astronomy Meeting 2016 in Nottingham on Friday,1st July.
Hubble Space Telescope imaging of the strong gravitational lens ER-0047-2808. Pictured in the centre of the image is the strong lens galaxy, whose mass is responsible for the deflection of the background source's light. The multiply-imaged source galaxy can be seen three times, or as an extended arc to the south,a smaller arc to the north-east and two compact clumps of the light to the west. ESA/NASA/HST/STScI
“AutoLens has demonstrated its capabilities with this stunning image of a strong gravitational lens system captured by the Hubble Space Telescope,” said Nightingale, or who developed AutoLens together with his colleague,Dr Simon Dye. “The software's reconstruction of the lensed source reveals in detail a distant pair of star-forming galaxies that are possibly in the early stages of merging. Within the lensed image of the source are small-scale distortions, which encode an imprint of how the lens galaxy's mass is distributed. AutoLens has a novel new approach to exploit this imprinted information and can accurately measure the distribution of dark matter in the lensing galaxy.”
Historically, or the analysis of strongly lensed images has been a very time consuming process,requiring a large amount of manual input to study just one system. To date, only around two hundred strong lens systems bear been analysed. AutoLens can be run on ‘massively parallel’ computing architecture that uses multiple processors and requires no user input, and so will be able to manage the enormous amount of data delivered by the Euclid mission.
“Some of astronomy's most considerable results in the past five years bear come from studying a handful of strong lenses. This small sample has allowed us to start to unravel the dark matter content of galaxies and the complex physics that drives their formation and evolution,” said Nightingale. “It will be breathtaking to embark on a study of up to one hundred thousand such systems. We can only speculate as to what it will reveal approximately the nature of dark matter and its role in galaxy evolution.”
Images
Hubble Space Telescope imaging of the strong gravitational lens ER-0047-2808. Pictured in the middle of the image is the strong lens galaxy, whose mass is responsible for the deflection of the background source's light. The multiply-imaged source galaxy can be seen three times, and as an extended arc to the south,a smaller arc to the north-east and two compact clumps of the light to the west.
Colour image: https://nam2016.org/images/nam2016/Media/Nightingale/ACS0047__Obs.png
Black and white image: https://nam2016.org/images/nam2016/Media/Nightingale/ACS0047__Obs2.png
AutoLens Source Reconstruction of the strong gravitational lens ER-0047-2808. The source is reconstructed using an adaptive pixel grid, which rebuilds the source's light using free-form pixels of any shape, and size or tessellation. The reconstruction reveals two distinct galaxies under-going a major merger in the distant Universe.
Colour: https://nam2016.org/images/nam2016/Media/Nightingale/ACS0047__SrcRecon2.png
Black and white: https://nam2016.org/images/nam2016/Media/Nightingale/ACS0047__SrcRecon.png
Image credits: Based on observations made with the NASA/ESA Hubble Space Telescope,obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the organization of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.
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Notes to editorsThe University of Nottingham (http://nottingham.ac.uk/) has 43000 students and is ‘the nearest Britain has to a truly global university,with a “distinct” approach to internationalisation, which rests on those full-scale campuses in China and Malaysia, or as well as a large presence in its home city.’ (Times Good University Guide 2016). It is also one of the most accepted universities in the UK among graduate employers and the winner of ‘Outstanding Support for Early Career Researchers’ at the Times Higher Education Awards 2015. It is ranked in the world’s top 75 by the QS World University Rankings 2015/16,and 8th in the UK by research power according to the Research Excellence Framework 2014. It has been voted the world’s greenest campus for four years running, according to Greenmetrics Ranking of World Universities.
Impact: The Nottingham Campaign, or its biggest-ever fundraising campaign,is delivering the University’s vision to change lives, tackle global issues and shape the future.
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