Astronomer Rudy Wijnands of Astronomical Institute Anton Pannekoek of the UvA has won the Bruno Rossi prize 2006 together with fellow scientists wetenschappers Deepto Chakrabarty (Massachusetts Institute of Technology) and Tod Strohmayer (NASA's Goddard Space Flight Center). The researchers are awarded the prize for their pioneering work  - partly independently, partly in cooperation - in the field of millisecond pulsations and oscillations of neutron stars in binary star systems.

The work of the three researchers on the signals transmitted in x-rays by these neutron stars is considered to be pioneering. The contribution of Wijnands was among other things the discovery in 1998 of the first millisecond x-ray pulsar.  These pulsars are neutron stars rotating around their axis around a 1000 times per second; matter from the accompanying star when falling on the surface of the pulsar is heated to the extent that x-rays are released. The matter current however is not homogeneous: it is bent off by the pulsar’s magnetic field and lumps of matter are formed which radiate extra x-rays when ‘spiralling’ inwards. This causes a mixture of periodical and quasi-periodical oscillations in its luminosity. These oscillations can be used for measuring the turning speed of the pulsar as well as for studying other pulsar characteristics. The observations of the three have mainly been done using NASA satellite Rossi X-ray Timing Explorer (RXTE).

The Bruno Rossi prize is the highest distinction in high-energy astrophysics and has been established in honour of the Italian-American astronomer Prof. Bruno Rossi, the ‘grandfather of high-energy astrophysics’ and one of the moving forces behind the origins of x-ray astronomy. The department of high-energy astrophysics of the American Astronomical Society (AAS) awards the prize yearly and it will this time be presented during the general meeting of the AAS in early 2007. It will be the third time for an UvA astronomer to receive the prize; earlier winners were Jan van Paradijs and Michiel van der Klis.