Search

LOFAR (the Low Frequency Array) is the largest radio telescope in the world for observing low frequency radio emission from 10 to 240 MHz. In addition to its use as an interferometric array, LOFAR is now routinely used to detect cosmic ray induced air showers by their radio emission. The LOFAR core in the Netherlands has a higher density of antennas than any dedicated cosmic ray experiment in radio. On an area of $12 \mathrm{km}^2$ more than 2300 antennas are installed. They measure the radio emission from air showers with unprecedented precision and, therefore, give the perfect opportunity to disentangle the physical processes which cause the radio emission in air showers. In parallel to ongoing astronomical observations LOFAR is triggered by an array of particle detectors to record time-series containing cosmic-ray pulses. Cosmic rays have been measured with LOFAR since June 2011. We present the results of the first year of data., Comment: Accepted for AIP Conference Proceedings, ARENA 2012, Erlangen, Germany

Ultra-high-energy neutrinos and cosmic rays produce short radio flashes through the Askaryan effect when they impact on the Moon. Earthbound radio telescopes can search the Lunar surface for these signals. A new generation of low- frequency, digital radio arrays, spearheaded by LOFAR, will allow for searches with unprecedented sensitivity. In the first stage of the NuMoon project, low-frequency observations were carried out with the Westerbork Synthesis Radio Telescope, leading to the most stringent limit on the cosmic neutrino flux above 10$^{23}$ eV. With LOFAR we will be able to reach a sensitivity of over an order of magnitude better and to decrease the threshold energy., Comment: Proceedings of the ARENA 2012 workshop (Erlangen, Germany), AIP Conference Proceedings, to be published