Giant pulse on two bands

Image may be NSFW.
Clik here to view.© CC-BY 4.0 Tammo Jan Dijkema

This shows a giant pulse of the Crab pulsar, which we observed on 17 January with the Dwingeloo telescope. We recorded this pulse with the two feeds in the focus of the telescope, each attached to a software defined radio (SDR). On 1300-1400 MHz we recorded 100 MHz of bandwidth, while on 400-420 MHz we recorded 20 MHz. The 20 MHz was not limited by the SDR, but by the amount of clean spectrum.

The picture shows the effect of dispersion: at the high frequencies, the radio emission arrives a good second earlier than at the low frequencies. The red lines show the theoretical dispersion.

The two top inset plots show the folded data after correcting for dedispersion (top), the dedispersed spectrum around the pulse (middle) and a DM-time diagram.

We are planning to use this set-up to detect other kinds of giant pulses as well.