Processing LOFAR telescope data in real time on a Blue Gene/P supercomputer

This paper gives an overview of the LOFAR correlator. Unlike traditional telescopes, the correlator is implemented in software, yielding a very flexible and reconfigurable instrument. The term “correlator” understates its capabilities: it filters, corrects, coherently or incoherently beam forms, dedisperses, and transforms the data as well. It supports several observation modes, even simultaneously. The high data rates and processing requirements compel the use of a supercomputer; we use a Blue Gene/P. The software is highly optimized and achieves extremely good computational performance and bandwidths, increasing the performance of the entire LOFAR telescope.