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Fully automated analysis software takes on Euclid's 100,000 strong gravitational lens challenge

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The European Space Agency’s Euclid satellite, due for launch in 2020, will set astronomers a huge challenge: to analyse one hundred thousand strong gravitational lenses. In preparation for Euclid’s challenge, researchers fromThe University of Nottingham have developed ‘AutoLens’, the first fully-automated analysis software for strong gravitational lenses. 

James Nightingale, a PhD student in the School of Physics and Astronomy, will present the first results from ‘AutoLens’ on Friday, 1st July at the National Astronomy Meeting 2016, taking place in Nottingham on the University’s Jubilee Campus. The event is organised by the Royal Astronomical Society.

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, but are also valuable tools for probing our Universe.

AutoLens was developed by James Nightingale together with his colleague Dr Simon Dye.

James said: “AutoLens has demonstrated its capabilities with this stunning image of a strong gravitational lens system captured by the Hubble Space Telescope. 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, 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 have been analysed. AutoLens can be run on ‘massively parallel’ computing architecture that uses multiple processors and requires no user input, so will be able to manage the huge amount of data delivered by the Euclid mission.

James said: “Some of astronomy’s most important results in the past five years have 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. 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 about the nature of dark matter and its role in galaxy evolution.”

Hubble Space Telescope imaging of the strong gravitational lens ER-0047-2808. Pictured in the center 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, as an extended arc to the south, a smaller arc to the north-east and two compact clumps of the light to the west.

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, size or tessellation. The reconstruction reveals two distinct galaxies under-going a major merger in the distant Universe. 

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 Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

Posted on Friday 8th July 2016

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