Werner Becker MPE

  Title: 

     Pulsars - cosmic beacons seen by ROSAT

  Abstract:

     Neutron stars are among the most fascinating astronomical objects
     in the universe. Born in the imploding core of a supernova, they
     provide a unique class of stellar objects with properties that
     make them nearly ideal probes for investigating a wide variety
     of physical problems. Currently, nearly 800 neutron stars are known
     as rotation-powered pulsars. In the course of the ROSAT and ASCA
     mission, about 10\% of them have been observed in detailed pointed
     observations, leading to the detection of pulsed X-ray emission from
     15 of them while 18 more pulsars are identified only by positional
     coincidence with a radio pulsar.

     One primary goal addressed with ROSAT was to search for thermal X-ray
     emission from cooling neutron stars. The close link between the thermal
     evolution of neutron stars and the physical characteristics of neutron
     star material at super-nuclear densities provides an important starting
     point for the empirical study of matter at extreme energies and baryon
     densities. Comparing the neutron star temperatures and temperature
     upper limits measured by ROSAT with the theoretical predictions based
     on different equations of state thus provides the empirical basis
     essential for the verification of neutron star models and cooling
     theories.