Neutron Stars and Their Birth Events

This volume is the documentation of the second Course on 'Neutron Stars, Active Galactic Nuclei and Jets', held at Erice in September 1988. This second Course was devoted to our knowledge about neutron-star sources. The poster spoke of: pulsars, accreting X-ray sources and jet englnes, perhaps also UHE pulsars, X- ra~' bursters and black-hole candidat.es. Neutron stars have even been proposed as the primary cosmic-ray boosters. Most of theil' properties are stil1 controversial, such as their birth mechanism (neutrino versus magnetic piston), internal structure (neutrons, quarks, strange particles), magnetic, thermal and spin histories, wind generation (hydrogen versus pair plasma, radiation versus centrifugal pressure), magnetospheric structure and accretion modes (along field lines versus quasi-Keplerian). The listed controversies have largely survived through the Course and entered into the proceedings. Several lecturers speak of 'magnetic-field decay' in neutron stars, of the 'recycling' of old pulsars, and of 'accretion-induced collapse' of white dwarfs as though such processes were textbook knowledge. Terms and abbreviations like RPSR (=recycled pulsar), spinup line, AIC, and ADC (=accretion disk corona) help to foster the assumptions. It is not clear to me at this time whether any of these notions has an application to reality.