Dynamics of neutron stars and binaries in globular clusters or, Ménages à trois: revitalizing burnt out degenerates through partner swapping

[摘要] Interaction cross-sections and collision cross-sections for a set of hard multi-mass binary-single star interactions are calculated in order to estimate three-body collision cross-sections in galactic globular clusters. The cross-sections are calculated by direct integration of binary-single star encounters, using Monte Carlo sampling to average over the three-body phase space. A number of mass-ratios physically relevant to the globular cluster environment are used. Differential energy transfer rates due to three-body interactions are calculated. Parametricapproximations for the various cross-sections calculated are found.The results of the cross-sections are used to evaluate various formation scenarios for the pulsars PSR2127+11C (M15C) and PSR1744-24A (TER5A). In addition the contribution of the globular cluster system to the galactic birthrate of PSR1913+16 type systems is estimated.The dynamics and interactions of a test binary population in a number of globular cluster models are calculated in a static background. The cluster method used are isotropic multi-mass King models of varying concentration and density.The model developed is generalisable to an arbitrary cluster distribution function, including one evolving in time. Relative probabilities of different encounters arefound for binaries on arbitrary trajectories in the various cluster models. The actual interaction rates of the test population are calculated by direct integration, using Monte Carlo sampling to average over the initial binary parameters. The number of neutron stars expected to be recycled in different concentration clusters is estimated with a particular view to understanding the pulsar population observed in clusters 47Tuc and M15.Estimates are also made of the binary density profile of the different concentration class clusters, and the final distribution in binary parameters. The production rate of "blue stragglers" and the interaction rate of (sub)giants and white dwarfs in the various clusters are also estimated.

[发布机构] University:California Institute of Technology;Department:Physics, Mathematics and Astronomy

[关键词] Physics