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G.J. Francischelli (State University of New York at Stony Brook)
Accretion onto a compact star is one of the most efficient energy sources known to nature. Since the discovery of X-ray pulsars in the 1970s, it has become commonly accepted that the source of a large fraction of discrete, Galactic X-ray sources are accreting neutron stars. The presence of a strong magnetic field can channel the inflow of material onto a neutron star, often yielding measurable changes in its rotation rate and field strength. For my thesis, I have analyzed this evolution in detail for several types of systems. I have written a computer code that traces the evolution of an accreting neutron star's spin and surface magnetic field. The model was first applied to the case of a helium star, neutron star binary, considered the progenitor of relativistic binary pulsars. Additionally, I have studied the evolution of isolated neutron stars accreting from fossil disks and have determined that such models are unable to explain many observational features of anomalous X-ray pulsars (AXPs). Finally, while there is no universally accepted model of magnetic field decay in neutron stars, most agree that it seems to correlate with overall accretion time. As pulsar lifetime is inversely related to its surface magnetic field, the probability of observing an accreting system is enhanced. We have applied this "observability premium" to a population synthesis model of relativistic binary pulsars.
The author(s) of this abstract have provided an email address for comments about the abstract: francis@mail.astro.sunysb.edu
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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.