Sensitivity Analysis of a Space-borne Gravitational Wave Detector

Abstract

Abstract : Modern theories of gravity predict ripples in space and time, which are known as gravitational waves. Very large interacting masses, such as binary systems of neutron stars or black holes, are predicted to generate gravitational waves that may be intense enough to bevvv detected. This study presents a response analysis for the proposed gravitational wave experiment known as the Laser Interferometer Space Antenna (LISA). The analysis focuses on the gravitational wave distortion patterns, or polarizations, predicted by the Brans-Dicke Scalar-Tensor Theory of Gravity (BD). LISA, a cooperative venture between the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA), is a proposed space-based gravitational wave experiment with the potential to distinguish between polarizations of gravitational waves. LISA is scheduled for launch in 2012; so much of the current work for LISA involves the development and design of systems and procedures that will allow LISA to attain its desired performance. For a gravitational wave experiment, the projected sensitivity is determined by an instrument response function, which relates the disturbance generated by the gravitational wave to the disturbance that can be measured by the instrument. This study compares the response functions for BD polarizations to the published response functions for GR. Response functions co-responding to several different methods of data collection were analyzed. To numerically evaluate and compare the response functions, two programs were generated in the MATLAB programming language. The first program computes the response functions averaged over all source directions for each gravitational wave polarization and data collection method. The second program calculates the instrument response at each point in LISA s orbit to gravitational waves originating from the galactic center.