A Search for Gravitational Radiation from PSR 1937+214

Citation

Hereld, Mark (1984) A Search for Gravitational Radiation from PSR 1937+214. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/gyg6-rj98. https://resolver.caltech.edu/CaltechTHESIS:10302018-175018310

Abstract

A search for gravitational radiation from the "millisecond pulsar", PSR 1937+214, using a 40 meter baseline laser interferometric detector is described. Four days of observation yielded 1.2 x 10⁵ seconds of data. Throughout the experiment, the pulsar phase was synthesized to an accuracy of better than one tenth of the pulsar period. A trigger generated from this signal synchronized the data averaging. Narrow band amplitude spectra centered at the pulsar's fundamental electromagnetic pulsation frequency (~642 Hz) and its first harmonic were obtained. The spectra, one for each combination of polarization and center frequency, place 99.7% confidence level limits on the emitted gravitational radiation. In dimensionless strain, h, the rms limits are:

642 Hz "plus" polarization 1.6 x 10^-17

" "cross" " 3.1 x 10^-17

1294 Hz "plus" polarization 1.1 x 10^-17

" "cross" " 1.5 x 10^-17

Over the four day observing period, the performance of the detector varied with changing temperature. During the stable night hours, the two optical cavities remained locked to reflection minima for 20 to 80 minutes before momentarily losing lock. Temperature changes of 1° to 2°C in the morning and evening necessitated compensating adjustments to the optics to maintain good fringe visibility.

The interferometer senses changes in the separations between three test masses. The test masses hang like pendulums so that they are free to move in response to gravitational radiation. The suspension system is designed to provide passive isolation from seismic and environmental vibration noise. The orientation of each test mass is stabilized with a feedback loop. The design of the test masses, their suspension systems, and the servo system which controls their orientation is described.

Thesis Files