| Description: | The movie shows the effect of lightning discharges in stormy weather have on images of the radio sky as they pass over the LOFAR core. The images (one per second) were made with the AARTFAAC instrument (www.aartfaac.org) using the LBA dipoles of the six LOFAR super-terp stations. This particular storm occurred on June 04, 2019, as indicated in the top left corner. The horizon indicator with compass marks runs along the image edge, and some of the brightest radio sources on the sky as well as the little dipper constellation outline are marked as overlays on the image.
Lightning discharges generate strong radio waves which are picked up by the instrument and cause the calibration of the data to fail, resulting in the images of the brightest radio sources to streak across the image. Sometimes, the lightning events (many of them) are localized as a point source of radio emission somewhere on the sky, as the thundercloud passes overhead. |
