| Description: | In tied-array beamforming we coherently combine the signals from all LOFAR stations and as such it enables us to use the entire LOFAR sensitivity in specific directions on the sky. In the image above we showcase the first successful demonstration of tied-array beamforming on CEP. Pulsar data was recorded separately with the four individual tiles (left panel) and saved on BG/P. There, appropriate weights were applied and the complex voltages were summed, producing a coherent beam that is equivalent to one of a hypothetical 4-times-larger tile (right panel). We were therefore happy to see the pulsar signal-to-noise ratio increase by the expected factor of 4.
The above demonstration is major step in the realization of tied-array beamforming for LOFAR, as the very software used here will be optimized and scaled up all the way to all LOFAR stations and many parallel beams. Now that we have a working version in place for the current LOFAR we can test many basic steps now, while steadily optimizing as the hardware rolls out; so as to be ready for science as early as possible. Tied-array beamforming enables high gain, high time resolution studies of known discrete sources (planets, pulsars) while with multiple parallel beams, one can also survey the sky for new pulsars and fast transients. |
