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ERC "DARKLIGHT" project led by Luigi Guzzo was concluded

At the end of 2017, the Darklight project led by Luigi Guzzo, Professor of Cosmology in this Department, was officially concluded. The project has been supported by a 1.72 million euro Advanced Research Grant awarded in 2012 by the European Research Council (ERC). Its central goal has been to improve the techniques and models through which cosmological information is extracted from statistical measurements of the large-scale galaxy distribution in large galaxy surveys. This is particularly important for those measurements that could signal deviations from General Relativity in the large-scale behaviour of gravity. Such information is encrypted in the observed galaxy clustering, hidden by both observational biases and modelling limitations.

Darklight developed new techniques, which were first tested on large n-body simulations and then applied to the new VIPERS survey, built with the Very Large Telescope (VLT) of ESO, in Chile by an international group (led by Prof. Guzzo). VIPERS built the largest spectroscopic map of galaxies ever made with ESO's telescopes (90,000 galaxies).  Thanks to the Darklight analyses, VIPERS delivered novel measures of the growth rate of structure at an epoch when the Universe was about half its current age (estimated at 13.8 billion years), which are in agreement, within the error bars, with the predictions of Einstein's theory. These results further confirm the standard cosmological model, which requires the presence of the mysterious "Cosmological Constant" to explain the observation (Nobel Prize 2011) that the speed of expansion of the Universe is increasing.


In the five years of its development, the Darklight research group financially supported six international postdocs (coming from USA, F, UK, J, and I) and two PhD students; the group also hosted four other PhD students and seven Master students. Most of these are now continuing their careers in the academia, spreading through Europe the knowledge and skills learned through Darklight. These skills will be precious for the analysis of the next generation of galaxy maps, as that planned by Euclid, the ESA satellite due to launch in 2022 in which Luigi Guzzo and his group play a leading role.

22 January 2018
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