Pulsar Science in Europe

Pulsar Physics and Extreme, Magnetized Plasmas

The physical conditions on and nearby neutron stars are extreme; with a composition that is up to ten times the nuclear density, typical surface magnetic fields of 1000 billion times that of the Earth and atmospheres with potential differences of 1000 billion Volts, neutron stars are unlike any object within our daily experience. After almost 40 years of study, although the basic principles of the pulsar emission mechanism are known, the details of the highly complex process are not understood. Some of the fundamental questions are:

One of the reasons for the slow progress over the years has been a lack of really high quality data showing the neutron star emission at many different parts of the electromagnetic spectrum. To address this, PulSE team members have combined their observing resources to carry out simultaneous multi-frequency observations of individual pulses from pulsars. This work has been so successful that collaborators using other telescopes have joined in the observations to broaden the frequency coverage. An example is shown below for the nearby 1.2-s pulsar B1133+16.

A 22-s data slice showing the pulsed radiation at four different frequency bands obtained during coordinated observations with three telescopes: the Giant Metre Wave Radio Telescope (GMRT) in India, the Lovell telescope in the UK and the Effelsberg telescope in Germany. Visit the Video section for animations showing simultaneous observations.

These observations have provided important constraints on the emission within the radio band. In recent years, observations have been carried out including optical and X-ray observations. Simultaneous observations of the giant pulses of the Crab pulsar at both radio and optical frequencies revealed an unexpected correlation between these to regimes as published in Science. The observations required both sensitive radio observations of the giant pulses themselves, provided by Westerbork and Effelsberg in the latest experiments, and accurate timing information, obtained from regular Lovell telescope measurements.

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