The Large European Array for Pulsars project is a key component of the European Pulsar Timing Array (EPTA) collaboration to tie together the five 100-m class telescopes in Europe to make a phased array telescope for high precision pulsar timing.
The LEAP project uses pulsar observations from the 76-m Lovell telescope in England, the 94-m Nancay Radio Telescope in France, the 100-m Effelsberg telescope in Germany, the 94-m Westerbork Synthesis Radio Telescope in the Netherlands and the 64-m Sardinia Radio Telescope in Italy. Using specialized software, the observations are combined into a phased array telescope with a diameter equivalent to that of a 194-m telescope. The increased sensitivity of the phased array telescope has allowed us to improve pulsar timing accuracy and observe more and fainter pulsars than was presently possible with the telescopes in Europe.
The goal of the LEAP project and the EPTA is to use pulsar timing to directly detect gravitational waves. The flexing of space-time by the passage of gravitational waves between the Earth and a pulsar will introduce a residual time delay in the arrival time of pulses from the pulsar on Earth. By accurately timing the arrival times of pulses from several pulsars distributed along the sky we will look for correlated residuals which would be caused by gravitational waves.