Abstract
The results of recent soft X-ray and optical searches for quiescent gamma ray burster counterparts are used to constrain the properties of the neutron stars responsible for bursters. Ages are restricted to the range 2×105 y and above based on temperature upper limits and theoretical cooling curves, or 107 y and above if bursters have evolved from pulsars. Velocities are greater than 20 km/s if the neutron stars are unmagnetized. Practically no main sequence star could have escaped detection in the optical/IR searches, so if the neutron stars are in binary systems, the companion is most likely a degenerate, low mass, low temperature object.
Publisher
Cambridge University Press (CUP)