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Session 73 - White Dwarfs, Neutron Stars and Pulsars.
Display session, Thursday, June 13
Recent data on pulsar proper motions, along with a recalibration of the pulsar distance scale, has led to a reformation of the pulsar velocity distribution. Estimates indicating high mean pulsar velocities ( \sim 450 km/s) and specific cases of pulsars moving at velocities up to 2000 km/s seem to mandate some contribution to the pulsar motion at birth (namely, an asymmetry in the SN explosion). Although much work has been concentrated on extracting the actual pulsar motions from the observational data, none has attempted to derive the mean magnitude and distribution of neutron star kicks from asymmetric effects at pulsar birth. To gain some understanding of this distribution, we have performed monte-carlo simulations of both binary-star and galactic evolution, constraining many of the free-parameters through comparison with observations of massive progenitor systems (LMXBs, HMXBs, etc.). Despite uncertainties in the observational data and small number statistics, limits can be placed on the distribution of nascent kicks. In addition, we predict the expected observational signatures of pulsar velocities derived from specific natal kick distributions. These current and future limits are then discussed in the context of current kick mechanisms (including the new "fall-back" mechanism).
Program listing for Thursday