Gravity Waves from Rotating Neutron Stars and Evaluation of Fast Chirp Transform Techniques.pdf

a r X i v : a s t r o - p h / 0 1 0 9 5 5 9 v 1 2 8 S e p 2 0 0 1 Gravity Waves from Rotating Neutron Stars and Evaluation of Fast Chirp Transform Techniques Tod E. Strohmayer? § ? Laboratory for High Energy Astrohphysics, NASA/GSFC, Greenbelt, MD, 20771 Abstract. X-ray observations suggest that neutron stars in low mass X-ray binaries (LMXB) are rotating with frequencies from 300 - 600 Hz. These spin rates are significantly less than the break-up rates for essentially all realistic neutron star equations of state, suggesting that some process may limit the spin frequencies of accreting neutron stars to this range. If the accretion induced spin up torque is in equilibrium with gravitational radiation losses, these objects could be interesting sources of gravity waves. I present a brief summary of current measurements of neutron star spins in LMXBs based on the observations of high-Q oscillations during thermonuclear bursts (so called “burst oscillations”). Further measurements of neutron star spins will be important in exploring the gravitational radiation hypothesis in more detail. To this end I also present a study of fast chirp transform (FCT) techniques as described by Jenet Prince (2000) in the context of searching for the chirping signals observed during X-ray bursts. 1. Introduction X-ray binaries are potentially among the most interesting sources of gravitational wave emission which current and future gravity wave detectors will attempt to study. The high frequency gravity wave signal produced during binary inspiral and ring down of black hole and neutron star binaries contains detailed information on the properties of the compact object as well as the structure of spacetime in its vicinity. These objects will be prime targets for ground based detectors such as LIGO which because of seismic noise are only sensitive in the high frequency range above ～ 100 Hz. Neutron stars are compelling targets of investigation because of the extreme physical condition