The nature of matter at very high density is a problem of primary concern in modern physics research. Galactic neutron stars provide a unique opportunity to probe the properties of matter at densities inaccessible in terrestrial laboratories. A newly born neutron star is rapidly rotating and very hot. The subsequent rotational dynamics and thermal evolution provide valuable insight into the nature of the neutron star interior. Particularly interesting are neutron star glitches, remarkably sudden spin rate jumps involving changes in rotational energy of up to ~10^43 ergs. These puzzling phenomena are now generally ascribed to sudden angular momentum transfer to the crust from a more rapidly rotating neutron superfluid, though a self-consistent model for this process has yet to be proposed. The purpose of this project is to study glitches, both theoretically and observationally, as a means of probing very dense matter. Our approach includes simulations of the glitch process based on first principles, predictions of the short-term spin and thermal evolution of a neutron star, and comparison with pulsar timing data and surface temperature measurements.
The origin of cosmic gamma ray bursts (GRBs) remains a mystery some 25 years after their discovery. The BATSE data base, with its high time resolution, is a superb resource with which to study variability of GRBs and to thereby learn of the physical processes that generate them. We propose to study properties of GRB variability using statistical methods recently introduced to GRB research by Link, Epstein and Priedhorsky (1993). An autocorrelation function will be used to measure the characteristic durations of structures within a burst. The skewness function, a measure of a burst's temporal asymmetry, will be used to compare the relative rates of the intensity rise and fall over a large range in time scales. The autocorrelation and skewness analyses shed light on the explosive processes that generate GRBs and test, for example, whether rotating beams are involved. We will look for correlations between the time scales of burst structures and intensities to search for evidence of cosmological evolution.
| Mail: | Dr. Bennett Link |
|
Department of Physics |
| Montana State University | |
| Bozeman, MT 59717-3840 |
| E-mail: | blink@dante.physics.montana.edu |
| Phone: | (406) 994-6174 |
| FAX: | (406) 994-4452 |
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