Tuesday, 18 September 2012
First pulsar observation at KAIRA
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.