Tuesday, 18 September 2012

First pulsar observation at KAIRA

PSR J0332+5434 observed in single station mode with 31 subbands. The dedispersed signal is shown on the left hand side, while the original incoming signal is shown on the top right hand side. The lower left plot shows the power averaged across all 31 subbands after dedispersion. 

Today we tried something different. Instead of looking at our local atmospheric plasma, we looked at interstellar plasma, this time with the help of a pulsar. In this case, PSR J0332+5434, which is the brightest pulsar in the northern hemisphere.

Pulsars are highly magnetized neutron stars that spin very fast. This spinning movement causes broadband radio emissions due to acceleration of charged particles in the magnetic field of the pulsar. Due to the fact that the interstellar space contains charged particles (although typically less than one electron per cubic centimeter), the broadband pulse arrives to us at different delays for different frequencies. This is a familiar phenomena for radio waves travelling in our own local ionosphere, although the scales are much larger. In order to improve signal statistics, this dispersion has to be measured and also corrected for before averaging over wider bandwidths.

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