{"id":13595,"date":"2016-12-07T06:00:27","date_gmt":"2016-12-07T11:00:27","guid":{"rendered":"http:\/\/hobbyspace.com\/Blog\/?p=13595"},"modified":"2016-12-07T11:04:22","modified_gmt":"2016-12-07T16:04:22","slug":"13595","status":"publish","type":"post","link":"https:\/\/hobbyspace.com\/Blog\/?p=13595","title":{"rendered":"ESO: New study finds smoother dark matter distribution than earlier observations"},"content":{"rendered":"

The latest report from the\u00a0ESO<\/a>\u00a0(European Southern Observatory):<\/p>\n

Dark Matter May be Smoother than Expected
\n<\/a><\/strong>Careful study of large area of sky imaged by VST reveals intriguing result<\/em><\/p>\n

Analysis of a giant new galaxy survey, made with ESO\u2019s VLT Survey Telescope in Chile, suggests that dark matter may be less dense and more smoothly distributed throughout space than previously thought. An international team used data from the Kilo Degree Survey (KiDS) to study how the light from about 15 million distant galaxies was affected by the gravitational influence of matter on the largest scales in the Universe. The results appear to be in disagreement with earlier results from the Planck satellite.<\/p>\n

\"This<\/a>
This map of dark matter in the Universe was obtained from data from the KiDS survey, using the VLT Survey Telescope at ESO\u2019s Paranal Observatory in Chile. It reveals an expansive web of dense (light) and empty (dark) regions. This image is one out of five patches of the sky observed by KiDS. Here the invisible dark matter is seen rendered in pink, covering an area of sky around 420 times the size of the full moon. This image reconstruction was made by analysing the light collected from over three million distant galaxies more than 6 billion light-years away. The observed galaxy images were warped by the gravitational pull of dark matter as the light travelled through the Universe. Some small dark regions, with sharp boundaries, appear in this image. They are the locations of bright stars and other nearby objects that get in the way of the observations of more distant galaxies and are hence masked out in these maps as no weak-lensing signal can be measured in these areas. [Larger images.<\/a>]<\/em><\/figcaption><\/figure>Hendrik Hildebrandt from the Argelander-Institut f\u00fcr Astronomie<\/a> in Bonn, Germany and Massimo Viola from the Leiden Observatory in the Netherlands led a team of astronomers [1]<\/a> from institutions around the world who processed images from the Kilo Degree Survey<\/a> (KiDS), which was made with ESO\u2019s VLT Survey Telescope<\/a> (VST) in Chile. For their analysis, they used images from the survey that covered five patches of the sky covering a total area of around 2200 times the size of the full Moon [2]<\/a>, and containing around 15 million galaxies.<\/p>\n

By exploiting the exquisite image quality available to the VST at the Paranal site, and using innovative computer software, the team were able to carry out one of the most precise measurements ever made of an effect known as cosmic shear<\/a>. This is a subtle variant of weak gravitational lensing<\/a>, in which the light emitted from distant galaxies is slightly warped by the gravitational effect of large amounts of matter, such as galaxy clusters<\/a>.<\/p>\n