Daily Image
19-12-2007
LOFAR weathers the elements
| Submitter: | Menno Norden |
| Description: | From a hardware survival point of view, one of the most interesting LOFAR observations of the past year was done with LOFAR test station CS001c, for two and a half days, with the Low Band Antennas. The data shows very strong noisy signals, which were identified as emanating from sporadic (but violent) natural phenomena. The first signal is a very powerful Solar flare. The level is limited here to -72 dB, but in reality it was much stronger. But, harking to Johan Cruijff, the greatest living Dutch philosopher ("elk nadeel hep se foordeel"), we turn this to our advantage: Such a flare can be used to validate the system because it is a very strong, dominating point-source, with 100% circular polarization. The second signal was due to heavy rainfall. This causes a shift (down) of the resonance peak of the LBA. This means less power above the resonance frequency (59 MHz). The last signal is due to lightning strikes near Exloo. The first were detected a 100 km before the thunderstorm passed Exloo. The last strike, over the north German islands, was also detected with LOFAR. |
| Copyright: | Astron |
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